Compositions of ethylene / alpha-olefin multi-block interpolymer for blown films with high hot tack

ABSTRACT

The present invention relates to film layers and compositions having improved hot tack properties. The compositions comprise at least one ethylene/α-olefin interpolymer, wherein the ethylene/α-olefin interpolymer may have, for example, a Mw/Mn from about 1.7 to about 3.5, at least one melting point, Tm, in degrees Celsius, and a density, d, in grams/cubic centimeter, wherein the numerical values of Tm and d correspond to the relationship: 
         Tm &gt;−2002.9+4538.5( d )−2422.2( d )2.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. Ser. No.11/376,971, which claims priority to PCT Application No.PCT/US2005/008917 (Dow 63558D), filed on Mar. 17, 2005, which in turnclaims priority to U.S. Provisional Application No. 60/553,906, filedMar. 17, 2004. The application further claims priority to U.S.Provisional Application Ser. No. 60/717,982 filed Sep. 16, 2005 (Dow64437). For purposes of United States patent practice, the contents ofthe provisional applications and the PCT application are hereinincorporated by reference in their entirety.

FIELD OF THE INVENTION

This invention relates to ethylene/α-olefin multi-block interpolymercompositions having hot tack properties and films made therefrom.

BACKGROUND AND SUMMARY OF THE INVENTION

It is often desirable to coat an article, substrate or film in order tomodify the properties. A particularly desirable coating is that of aheat-sealable film, i.e., a film which is capable of being bonded toitself, another film or another substrate with the application of heatand/or pressure. In this manner, the article, substrate or film can besealed to form structures such as bags or other packaging materials.

Laminates and single or multi-layer films are two packaging materialsthat often employ heat-sealable layers. Laminates are conveniently madeby coating a substrate, for example, paper or film, with a heat-sealablelayer by extrusion coating. Extrusion coating is a process whereby apolymer or blend of polymers is fed into an extruder hopper. In thehopper the polymer or blend is melted and passed through a die to form aweb. The web is then extruded onto the substrate through a niproll/chill roll interface, for example, so that the molten web ispressed onto the substrate. The substrate is cooled by the chill rolland the wound up at a winder.

Similarly, many different processes are often employed to make single ormulti-layer films which are useful as packaging materials. Suchprocesses can include bubble extrusion and biaxial orientationprocesses, as well as, tenter frame techniques. In order to facilitatesealing, the heat-sealable film is usually employed singly or as theoutermost or innermost layer in the case of multi-layer films.

Laminates and single or multi-layer films having a heat-sealable filmlayer are often used in “form, fill, and seal” machines. These machinescreate from film a continuous stream of packages that are capable ofbeing closed by film-to-film seals. Often such packages are sealed viaheat seal jaws that apply heat and pressure to form the film-to-filmseal closure.

The heat seal closures made via the heat seal jaws will often bestrongest after the seal has cooled to ambient temperature. However, inorder to increase the production capacity, the packages are often filledwith product before the bottom seal has had time to completely cool,therefore, the polymers at the seal interface haven't completelysolidified (or recrystallized) or they are still in a softened state.Thus, the closure must exhibit a sufficient strength very rapidlywithout the need for cooling to ambient temperature. Otherwise, theclosure will be destroyed by the weight of the product when the packageis filled.

“Seal strength” is the strength of a heat seal at ambient temperatureafter the seal has been formed and reached its full strength. However,as described above the properties of the seal at temperatures subsequentto formation but prior to cooling to ambient conditions are oftenimportant. The properties of seal strength at temperatures above ambientare often referred to as “hot tack” properties.

There are a number of different hot tack properties that are importantfor heat-sealable films. One important hot tack property is the“initiation temperature.” The initiation temperature is the firsttemperature above ambient at which a seal can be formed by applying agiven pressure to a given thickness of film for a given length of time.Often the initiation temperature is expressed as the minimum temperatureat which a 2 mil film forms a seal with a strength of 0.5N/in. usingASTM F 1921, Method B. In general, lower initiation temperatures aredesirable because less energy is required to be used to form the sealand also the less time it takes for the initial seal to form at a givenseal jaw temperature. Thus, production rates are capable of beingincreased.

Another important hot tack property is “ultimate hot tack.” Ultimate hottack is the largest strength the seal has at temperatures above theinitiation temperature. Usually it is desirable that the ultimate hottack occurs at the lowest possible temperature. Another hot tackproperty that is generally desirable is a wide processing window suchthat the film exhibits a suitable seal strength as measured over a broadtemperature range. Also generally desirable is high temperature hot tacksuch that the seal strength remains sufficient even at elevatedtemperatures.

The hot tack properties are often determined by the composition employedto form the film seal. In the past, compositions such as those describedin U.S. Pat. No. 4,339,507 and U.S. Pat. No. 5,741,861 that are amixture of, for example, low density polyethylene and linear low densityethylene hydrocarbon copolymer have been employed. Unfortunately,however, such compositions often have hot tack properties that may limitthe production capacity. The compositions of U.S. Pat. No. 6,262,174comprising, for example, mixtures of polypropylene and polyethylenes,solved many of the aforementioned problems. However, it is stilldesirable to discover new compositions that have improved hot tackproperties and broad melting temperature windows. In addition, forapplications in which ease of opening is desired (e.g. cereal boxes)compositions with controlled heat seal strength are desirable.

Advantageously, new compositions have been discovered which givesuperior hot tack properties, broad processing windows, and controlledheat seal strength. The compositions comprise one or moreethylene/α-olefin interpolymers. The compositions can further compriseone or more other polymers, as well as, one or more additives. Suitablefilm structures include both monolayer and multilayer films.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the melting point/density relationship for the inventivepolymers (represented by diamonds) as compared to traditional randomcopolymers (represented by circles) and Ziegler-Natta copolymers(represented by triangles).

FIG. 2 shows plots of delta DSC-CRYSTAF as a function of DSC MeltEnthalpy for various polymers. The diamonds represent randomethylene/octene copolymers; the squares represent polymer examples 1-4;the triangles represent polymer examples 5-9; and the circles representpolymer examples 10-19. The “X” symbols represent polymer examplesA*-F*.

FIG. 3 shows the effect of density on elastic recovery for unorientedfilms made from inventive interpolymers(represented by the squares andcircles) and traditional copolymers (represented by the triangles whichare various Dow AFFINITY® polymers). The squares represent inventiveethylene/butene copolymers; and the circles represent inventiveethylene/octene copolymers.

FIG. 4 is a plot of octene content of TREF fractionatedethylene/1-octene copolymer fractions versus TREF elution temperature ofthe fraction for the polymer of Example 5 (represented by the circles)and comparative polymers E and F (represented by the “X” symbols). Thediamonds represent traditional random ethylene/octene copolymers.

FIG. 5 is a plot of octene content of TREF fractionatedethylene/1-octene copolymer fractions versus TREF elution temperature ofthe fraction for the polymer of Example 5 (curve 1) and for comparativeF (curve 2). The squares represent Example F*; and the trianglesrepresent Example 5.

FIG. 6 is a graph of the log of storage modulus as a function oftemperature for comparative ethylene/1-octene copolymer (curve 2) andpropylene/ethylene-copolymer (curve 3) and for two ethylene/1-octeneblock copolymers of the invention made with differing quantities ofchain shuttling agent (curves 1).

FIG. 7 shows a plot of TMA (1 mm) versus flex modulus for some inventivepolymers (represented by the diamonds), as compared to some knownpolymers. The triangles represent various Dow VERSIFY® polymers; thecircles represent various random ethylene/styrene copolymers; and thesquares represent various Dow AFFINITY™ polymers.

DETAILED DESCRIPTION OF THE INVENTION General Definitions

“Polymer” means a polymeric compound prepared by polymerizing monomers,whether of the same or a different type. The generic term “polymer”embraces the terms “homopolymer,” “copolymer,” “terpolymer” as well as“interpolymer.”

“Interpolymer” means a polymer prepared by the polymerization of atleast two different types of monomers. The generic term “interpolymer”includes the term “copolymer” (which is usually employed to refer to apolymer prepared from two different monomers) as well as the term“terpolymer” (which is usually employed to refer to a polymer preparedfrom three different types of monomers). It also encompasses polymersmade by polymerizing four or more types of monomers.

The term “ethylene/α-olefin interpolymer” generally refers to polymerscomprising ethylene and an α-olefin having 3 or more carbon atoms.Preferably, ethylene comprises the majority mole fraction of the wholepolymer, i.e., ethylene comprises at least about 50 mole percent of thewhole polymer. More preferably ethylene comprises at least about 60 molepercent, at least about 70 mole percent, or at least about 80 molepercent, with the substantial remainder of the whole polymer comprisingat least one other comonomer that is preferably an α-olefin having 3 ormore carbon atoms. For many ethylene/octene copolymers, the preferredcomposition comprises an ethylene content greater than about 80 molepercent of the whole polymer and an octene content of from about 10 toabout 15, preferably from about 15 to about 20 mole percent of the wholepolymer. In some embodiments, the ethylene/α-olefin interpolymers do notinclude those produced in low yields or in a minor amount or as aby-product of a chemical process. While the ethylene/α-olefininterpolymers can be blended with one or more polymers, the as-producedethylene/α-olefin interpolymers are substantially pure and oftencomprise a major component of the reaction product of a polymerizationprocess.

The ethylene/α-olefin interpolymers comprise ethylene and one or morecopolymerizable α-olefin comonomers in polymerized form, characterizedby multiple blocks or segments of two or more polymerized monomer unitsdiffering in chemical or physical properties. That is, theethylene/α-olefin interpolymers are block interpolymers, preferablymulti-block interpolymers or copolymers. The terms “interpolymer” andcopolymer” are used interchangeably herein. In some embodiments, themulti-block copolymer can be represented by the following formula:

(AB)_(n)

where in is at least 1, preferably an integer greater than 1, such as 2,3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, or higher, “A”represents a hard block or segment and “B” represents a soft block orsegment. Preferably, As and Bs are linked in a substantially linearfashion, as opposed to a substantially branched or substantiallystar-shaped fashion. In other embodiments, A blocks and B blocks arerandomly distributed along the polymer chain. In other words, the blockcopolymers usually do not have a structure as follows.

AAA-AA-BBB-BB

In still other embodiments, the block copolymers do not usually have athird type of block, which comprises different comonomer(s). In yetother embodiments, each of block A and block B has monomers orcomonomers substantially randomly distributed within the block. In otherwords, neither block A nor block B comprises two or more sub-segments(or sub-blocks) of distinct composition, such as a tip segment, whichhas a substantially different composition than the rest of the block.

The multi-block polymers typically comprise various amounts of “hard”and “soft” segments. “Hard” segments refer to blocks of polymerizedunits in which ethylene is present in an amount greater than about 95weight percent, and preferably greater than about 98 weight percentbased on the weight of the polymer. In other words, the comonomercontent (content of monomers other than ethylene) in the hard segmentsis less than about 5 weight percent, and preferably less than about 2weight percent based on the weight of the polymer. In some embodiments,the hard segments comprises all or substantially all ethylene. “Soft”segments, on the other hand, refer to blocks of polymerized units inwhich the comonomer content (content of monomers other than ethylene) isgreater than about 5 weight percent, preferably greater than about 8weight percent, greater than about 10 weight percent, or greater thanabout 15 weight percent based on the weight of the polymer. In someembodiments, the comonomer content in the soft segments can be greaterthan about 20 weight percent, greater than about 25 weight percent,greater than about 30 weight percent, greater than about 35 weightpercent, greater than about 40 weight percent, greater than about 45weight percent, greater than about 50 weight percent, or greater thanabout 60 weight percent.

The soft segments can often be present in a block interpolymer fromabout 1 weight percent to about 99 weight percent of the total weight ofthe block interpolymer, preferably from about 5 weight percent to about95 weight percent, from about 10 weight percent to about 90 weightpercent, from about 15 weight percent to about 85 weight percent, fromabout 20 weight percent to about 80 weight percent, from about 25 weightpercent to about 75 weight percent, from about 30 weight percent toabout 70 weight percent, from about 35 weight percent to about 65 weightpercent, from about 40 weight percent to about 60 weight percent, orfrom about 45 weight percent to about 55 weight percent of the totalweight of the block interpolymer. Conversely, the hard segments can bepresent in similar ranges. The soft segment weight percentage and thehard segment weight percentage can be calculated based on data obtainedfrom DSC or NMR. Such methods and calculations are disclosed in aconcurrently filed U.S. patent application Ser. No. ______ (insert whenknown), Attorney Docket No. 385063-999558, entitled “Ethylene/α-OlefinBlock Interpolymers”, filed on Mar. 15, 2006, in the name of Colin L. P.Shan, Lonnie Hazlitt, et. al. and assigned to Dow Global TechnologiesInc., the disclose of which is incorporated by reference herein in itsentirety.

The term “crystalline” if employed, refers to a polymer that possesses afirst order transition or crystalline melting point (Tm) as determinedby differential scanning calorimetry (DSC) or equivalent technique. Theterm may be used interchangeably with the term “semicrystalline”. Theterm “amorphous” refers to a polymer lacking a crystalline melting pointas determined by differential scanning calorimetry (DSC) or equivalenttechnique.

The term “multi-block copolymer” or “segmented copolymer” refers to apolymer comprising two or more chemically distinct regions or segments(referred to as “blocks”) preferably joined in a linear manner, that is,a polymer comprising chemically differentiated units which are joinedend-to-end with respect to polymerized ethylenic functionality, ratherthan in pendent or grafted fashion. In a preferred embodiment, theblocks differ in the amount or type of comonomer incorporated therein,the density, the amount of crystallinity, the crystallite sizeattributable to a polymer of such composition, the type or degree oftacticity (isotactic or syndiotactic), regio-regularity orregio-irregularity, the amount of branching, including long chainbranching or hyper-branching, the homogeneity, or any other chemical orphysical property. The multi-block copolymers are characterized byunique distributions of both polydispersity index (PDI or Mw/Mn), blocklength distribution, and/or block number distribution due to the uniqueprocess making of the copolymers. More specifically, when produced in acontinuous process, the polymers desirably possess PDI from 1.7 to 2.9,preferably from 1.8 to 2.5, more preferably from 1.8 to 2.2, and mostpreferably from 1.8 to 2.1. When produced in a batch or semi-batchprocess, the polymers possess PDI from 1.0 to 2.9, preferably from 1.3to 2.5, more preferably from 1.4 to 2.0, and most preferably from 1.4 to1.8.

In the following description, all numbers disclosed herein areapproximate values, regardless whether the word “about” or “approximate”is used in connection therewith. They may vary by 1 percent, 2 percent,5 percent, or, sometimes, 10 to 20 percent. Whenever a numerical rangewith a lower limit, R^(L) and an upper limit, R^(U), is disclosed, anynumber falling within the range is specifically disclosed. Inparticular, the following numbers within the range are specificallydisclosed: R=R^(L)+k*(R^(U)−R^(L)), wherein k is a variable ranging from1 percent to 100 percent with a 1 percent increment, i.e., k is 1percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . , 50 percent,51 percent, 52 percent, . . . , 95 percent, 96 percent, 97 percent, 98percent, 99 percent, or 100 percent. Moreover, any numerical rangedefined by two R numbers as defined in the above is also specificallydisclosed.

Ethylene/α-Olefin Interpolymers

The ethylene/α-olefin interpolymers used in embodiments of the invention(also referred to as “inventive interpolymer” or “inventive polymer”)comprise ethylene and one or more copolymerizable α-olefin comonomers inpolymerized form, characterized by multiple blocks or segments of two ormore polymerized monomer units differing in chemical or physicalproperties (block interpolymer), preferably a multi-block copolymer. Theethylene/α-olefin interpolymers are characterized by one or more of theaspects described as follows.

In one aspect, the ethylene/α-olefin interpolymers used in embodimentsof the invention have a M_(w)/M_(n) from about 1.7 to about 3.5 and atleast one melting point, T_(m), in degrees Celsius and density, d, ingrams/cubic centimeter, wherein the numerical values of the variablescorrespond to the relationship:

T _(m)>−2002.9+4538.5(d)−2422.2(d)₂, and preferably

T _(m)≧−6288.1+13141(d)−6720.3(d)₂, and more preferably

T _(m)≧858.91−1825.3(d)+1112.8(d)².

Such melting point/density relationship is illustrated in FIG. 1. Unlikethe traditional random copolymers of ethylene/α-olefins whose meltingpoints decrease with decreasing densities, the inventive interpolymers(represented by diamonds) exhibit melting points substantiallyindependent of the density, particularly when density is between about0.87 g/cc to about 0.95 g/cc. For example, the melting point of suchpolymers are in the range of about 110° C. to about 130° C. when densityranges from 0.875 g/cc to about 0.945 g/cc. In some embodiments, themelting point of such polymers are in the range of about 115° C. toabout 125° C. when density ranges from 0.875 g/cc to about 0.945 g/cc.

In another aspect, the ethylene/α-olefin interpolymers comprise, inpolymerized form, ethylene and one or more α-olefins and arecharacterized by a ΔT, in degree Celsius, defined as the temperature forthe tallest Differential Scanning Calorimetry (“DSC”) peak minus thetemperature for the tallest Crystallization Analysis Fractionation(“CRYSTAF”) peak and a heat of fusion in J/g, ΔH, and ΔT and ΔH satisfythe following relationships:

ΔT>−0.1299(ΔH)+62.81, and preferably

ΔT≧−0.1299(ΔH)+64.38, and more preferably

ΔT≧−0.1299(ΔH)+65.95,

for ΔH up to 130 J/g. Moreover, ΔT is equal to or greater than 48° C.for ΔH greater than 130 J/g. The CRYSTAF peak is determined using atleast 5 percent of the cumulative polymer (that is, the peak mustrepresent at least 5 percent of the cumulative polymer), and if lessthan 5 percent of the polymer has an identifiable CRYSTAF peak, then theCRYSTAF temperature is 30° C., and ΔH is the numerical value of the heatof fusion in J/g. More preferably, the highest CRYSTAF peak contains atleast 10 percent of the cumulative polymer. FIG. 2 shows plotted datafor inventive polymers as well as comparative examples. Integrated peakareas and peak temperatures are calculated by the computerized drawingprogram supplied by the instrument maker. The diagonal line shown forthe random ethylene octene comparative polymers corresponds to theequation ΔT=−0.1299 (ΔH)+62.81.

In yet another aspect, the ethylene/α-olefin interpolymers have amolecular fraction which elutes between 40° C. and 130° C. whenfractionated using Temperature Rising Elution Fractionation (“TREF”),characterized in that said fraction has a molar comonomer contenthigher, preferably at least 5 percent higher, more preferably at least10 percent higher, than that of a comparable random ethyleneinterpolymer fraction eluting between the same temperatures, wherein thecomparable random ethylene interpolymer contains the same comonomer(s),and has a melt index, density, and molar comonomer content (based on thewhole polymer) within 10 percent of that of the block interpolymer.Preferably, the Mw/Mn of the comparable interpolymer is also within 10percent of that of the block interpolymer and/or the comparableinterpolymer has a total comonomer content within 10 weight percent ofthat of the block interpolymer.

In still another aspect, the ethylene/α-olefin interpolymers arecharacterized by an elastic recovery, Re, in percent at 300 percentstrain and 1 cycle measured on a compression-molded film of anethylene/α-olefin interpolymer, and has a density, d, in grams/cubiccentimeter, wherein the numerical values of Re and d satisfy thefollowing relationship when ethylene/α-olefin interpolymer issubstantially free of a cross-linked phase:

Re>1481−1629(d); and preferably

Re≧1491−1629(d); and more preferably

Re≧1501−1629(d); and even more preferably

Re≧1511−1629(d).

FIG. 3 shows the effect of density on elastic recovery for unorientedfilms made from certain inventive interpolymers and traditional randomcopolymers. For the same density, the inventive interpolymers havesubstantially higher elastic recoveries.

In some embodiments, the ethylene/α-olefin interpolymers have a tensilestrength above 10 MPa, preferably a tensile strength≧11 MPa, morepreferably a tensile strength≧13 MPa and/or an elongation at break of atleast 600 percent, more preferably at least 700 percent, highlypreferably at least 800 percent, and most highly preferably at least 900percent at a crosshead separation rate of 11 cm/minute.

In other embodiments, the ethylene/α-olefin interpolymers have (1) astorage modulus ratio, G′(25° C.)/G′(100° C.), of from 1 to 50,preferably from 1 to 20, more preferably from 1 to 10; and/or (2) a 70°C. compression set of less than 80 percent, preferably less than 70percent, especially less than 60 percent, less than 50 percent, or lessthan 40 percent, down to a compression set of 0 percent.

In still other embodiments, the ethylene/α-olefin interpolymers have a70° C. compression set of less than 80 percent, less than 70 percent,less than 60 percent, or less than 50 percent. Preferably, the 70° C.compression set of the interpolymers is less than 40 percent, less than30 percent, less than 20 percent, and may go down to about 0 percent.

In some embodiments, the ethylene/α-olefin interpolymers have a heat offusion of less than 85 J/g and/or a pellet blocking strength of equal toor less than 100 pounds/foot² (4800 Pa), preferably equal to or lessthan 50 lbs/ft² (2400 Pa), especially equal to or less than 5 lbs/ft²(240 Pa), and as low as 0 lbs/ft² (0 Pa).

In other embodiments, the ethylene/α-olefin interpolymers comprise, inpolymerized form, at least 50 mole percent ethylene and have a 70° C.compression set of less than 80 percent, preferably less than 70 percentor less than 60 percent, most preferably less than 40 to 50 percent anddown to close zero percent.

In some embodiments, the multi-block copolymers possess a PDI fitting aSchultz-Flory distribution rather than a Poisson distribution. Thecopolymers are further characterized as having both a polydisperse blockdistribution and a polydisperse distribution of block sizes andpossessing a most probable distribution of block lengths. Preferredmulti-block copolymers are those containing 4 or more blocks or segmentsincluding terminal blocks. More preferably, the copolymers include atleast 5, 10 or 20 blocks or segments including terminal blocks.

Comonomer content may be measured using any suitable technique, withtechniques based on nuclear magnetic resonance (“NMR”) spectroscopypreferred. Moreover, for polymers or blends of polymers havingrelatively broad TREF curves, the polymer desirably is firstfractionated using TREF into fractions each having an eluted temperaturerange of 10° C. or less. That is, each eluted fraction has a collectiontemperature window of 10° C. or less. Using this technique, said blockinterpolymers have at least one such fraction having a higher molarcomonomer content than a corresponding fraction of the comparableinterpolymer.

In another aspect, the inventive polymer is an olefin interpolymer,preferably comprising ethylene and one or more copolymerizablecomonomers in polymerized form, characterized by multiple blocks (i.e.,at least two blocks) or segments of two or more polymerized monomerunits differing in chemical or physical properties (blockedinterpolymer), most preferably a multi-block copolymer, said blockinterpolymer having a peak (but not just a molecular fraction) whichelutes between 40° C. and 130° C. (but without collecting and/orisolating individual fractions), characterized in that said peak, has acomonomer content estimated by infra-red spectroscopy when expandedusing a full width/half maximum (FWHM) area calculation, has an averagemolar comonomer content higher, preferably at least 5 percent higher,more preferably at least 10 percent higher, than that of a comparablerandom ethylene interpolymer peak at the same elution temperature andexpanded using a full width/half maximum (FWHM) area calculation,wherein said comparable random ethylene interpolymer has the samecomonomer(s) and has a melt index, density, and molar comonomer content(based on the whole polymer) within 10 percent of that of the blockedinterpolymer. Preferably, the Mw/Mn of the comparable interpolymer isalso within 10 percent of that of the blocked interpolymer and/or thecomparable interpolymer has a total comonomer content within 10 weightpercent of that of the blocked interpolymer. The full width/half maximum(FWHM) calculation is based on the ratio of methyl to methylene responsearea [CH₃/CH₂] from the ATREF infra-red detector, wherein the tallest(highest) peak is identified from the base line, and then the FWHM areais determined. For a distribution measured using an ATREF peak, the FWHMarea is defined as the area under the curve between T₁ and T₂, where T₁and T₂ are points determined, to the left and right of the ATREF peak,by dividing the peak height by two, and then drawing a line horizontalto the base line, that intersects the left and right portions of theATREF curve. A calibration curve for comonomer content is made usingrandom ethylene/α-olefin copolymers, plotting comonomer content from NMRversus FWHM area ratio of the TREF peak. For this infra-red method, thecalibration curve is generated for the same comonomer type of interest.The comonomer content of TREF peak of the inventive polymer can bedetermined by referencing this calibration curve using its FWHMmethyl:methylene area ratio [CH₃/CH₂] of the TREF peak.

Comonomer content may be measured using any suitable technique, withtechniques based on nuclear magnetic resonance (NMR) spectroscopypreferred. Using this technique, said blocked interpolymers has highermolar comonomer content than a corresponding comparable interpolymer.

Preferably, for interpolymers of ethylene and 1-octene, the blockinterpolymer has a comonomer content of the TREF fraction elutingbetween 40 and 130° C. greater than or equal to the quantity (−0.2013)T+20.07, more preferably greater than or equal to the quantity (−0.2013)T+21.07, where T is the numerical value of the peak elution temperatureof the TREF fraction being compared, measured in ° C.

FIG. 4 graphically depicts an embodiment of the block interpolymers ofethylene and 1-octene where a plot of the comonomer content versus TREFelution temperature for several comparable ethylene/1-octeneinterpolymers (random copolymers) are fit to a line representing(−0.2013) T+20.07 (solid line). The line for the equation (−0.2013)T+21.07 is depicted by a dotted line. Also depicted are the comonomercontents for fractions of several block ethylene/1-octene interpolymersof the invention (multi-block copolymers). All of the block interpolymerfractions have significantly higher 1-octene content than either line atequivalent elution temperatures. This result is characteristic of theinventive interpolymer and is believed to be due to the presence ofdifferentiated blocks within the polymer chains, having both crystallineand amorphous nature.

FIG. 5 graphically displays the TREF curve and comonomer contents ofpolymer fractions for Example 5 and comparative F to be discussed below.The peak eluting from 40 to 130° C., preferably from 60° C. to 95° C.for both polymers is fractionated into three parts, each part elutingover a temperature range of less than 10° C. Actual data for Example 5is represented by triangles. The skilled artisan can appreciate that anappropriate calibration curve may be constructed for interpolymerscontaining different comonomers and a line used as a comparison fittedto the TREF values obtained from comparative interpolymers of the samemonomers, preferably random copolymers made using a metallocene or otherhomogeneous catalyst composition. Inventive interpolymers arecharacterized by a molar comonomer content greater than the valuedetermined from the calibration curve at the same TREF elutiontemperature, preferably at least 5 percent greater, more preferably atleast 10 percent greater.

In addition to the above aspects and properties described herein, theinventive polymers can be characterized by one or more additionalcharacteristics. In one aspect, the inventive polymer is an olefininterpolymer, preferably comprising ethylene and one or morecopolymerizable comonomers in polymerized form, characterized bymultiple blocks or segments of two or more polymerized monomer unitsdiffering in chemical or physical properties (blocked interpolymer),most preferably a multi-block copolymer, said block interpolymer havinga molecular fraction which elutes between 40° C. and 130° C., whenfractionated using TREF increments, characterized in that said fractionhas a molar comonomer content higher, preferably at least 5 percenthigher, more preferably at least 10, 15, 20 or 25 percent higher, thanthat of a comparable random ethylene interpolymer fraction elutingbetween the same temperatures, wherein said comparable random ethyleneinterpolymer comprises the same comonomer(s), preferably it is the samecomonomer(s), and a melt index, density, and molar comonomer content(based on the whole polymer) within 10 percent of that of the blockedinterpolymer. Preferably, the Mw/Mn of the comparable interpolymer isalso within 10 percent of that of the blocked interpolymer and/or thecomparable interpolymer has a total comonomer content within 10 weightpercent of that of the blocked interpolymer.

Preferably, the above interpolymers are interpolymers of ethylene and atleast one α-olefin, especially those interpolymers having a wholepolymer density from about 0.855 to about 0.935 g/cm³, and moreespecially for polymers having more than about 1 mole percent comonomer,the blocked interpolymer has a comonomer content of the TREF fractioneluting between 40 and 130° C. greater than or equal to the quantity(−0.1356) T+13.89, more preferably greater than or equal to the quantity(−0.1356) T+14.93, and most preferably greater than or equal to thequantity (−0.2013)T+21.07, where T is the numerical value of the peakATREF elution temperature of the TREF fraction being compared, measuredin ° C.

Preferably, for the above interpolymers of ethylene and at least onealpha-olefin especially those interpolymers having a whole polymerdensity from about 0.855 to about 0.935 g/cm³, and more especially forpolymers having more than about 1 mole percent comonomer, the blockedinterpolymer has a comonomer content of the TREF fraction elutingbetween 40 and 130° C. greater than or equal to the quantity (−0.2013)T+20.07, more preferably greater than or equal to the quantity (−0.2013)T+21.07, where T is the numerical value of the peak elution temperatureof the TREF fraction being compared, measured in ° C.

In still another aspect, the inventive polymer is an olefininterpolymer, preferably comprising ethylene and one or morecopolymerizable comonomers in polymerized form, characterized bymultiple blocks or segments of two or more polymerized monomer unitsdiffering in chemical or physical properties (blocked interpolymer),most preferably a multi-block copolymer, said block interpolymer havinga molecular fraction which elutes between 40° C. and 130° C., whenfractionated using TREF increments, characterized in that every fractionhaving a comonomer content of at least about 6 mole percent, has amelting point greater than about 100° C. For those fractions having acomonomer content from about 3 mole percent to about 6 mole percent,every fraction has a DSC melting point of about 110° C. or higher. Morepreferably, said polymer fractions, having at least 1 mol percentcomonomer, has a DSC melting point that corresponds to the equation:

Tm≧(−5.5926)(mol percent comonomer in the fraction)+135.90.

In yet another aspect, the inventive polymer is an olefin interpolymer,preferably comprising ethylene and one or more copolymerizablecomonomers in polymerized form, characterized by multiple blocks orsegments of two or more polymerized monomer units differing in chemicalor physical properties (blocked interpolymer), most preferably amulti-block copolymer, said block interpolymer having a molecularfraction which elutes between 40° C. and 130° C., when fractionatedusing TREF increments, characterized in that every fraction that has anATREF elution temperature greater than or equal to about 76° C., has amelt enthalpy (heat of fusion) as measured by DSC, corresponding to theequation:

Heat of fusion (J/gm)≦(3.1718)(ATREF elution temperature inCelsius)−136.58,

The inventive block interpolymers have a molecular fraction which elutesbetween 40° C. and 130° C., when fractionated using TREF increments,characterized in that every fraction that has an ATREF elutiontemperature between 40° C. and less than about 76° C., has a meltenthalpy (heat of fusion) as measured by DSC, corresponding to theequation:

Heat of fusion (J/gm)≦(1.1312)(ATREF elution temperature inCelsius)+22.97.

ATREF Peak Comonomer Composition Measurement by Infra-Red Detector

The comonomer composition of the TREF peak can be measured using an IR4infra-red detector available from Polymer Char, Valencia, Spain(http://www.polymerchar.com/).

The “composition mode” of the detector is equipped with a measurementsensor (CH₂) and composition sensor (CH₃) that are fixed narrow bandinfra-red filters in the region of 2800-3000 cm⁻¹. The measurementsensor detects the methylene (CH₂) carbons on the polymer (whichdirectly relates to the polymer concentration in solution) while thecomposition sensor detects the methyl (CH₃) groups of the polymer. Themathematical ratio of the composition signal (CH₃) divided by themeasurement signal (CH₂) is sensitive to the comonomer content of themeasured polymer in solution and its response is calibrated with knownethylene alpha-olefin copolymer standards.

The detector when used with an ATREF instrument provides both aconcentration (CH₂) and composition (CH₃) signal response of the elutedpolymer during the TREF process. A polymer specific calibration can becreated by measuring the area ratio of the CH₃ to CH₂ for polymers withknown comonomer content (preferably measured by NMR). The comonomercontent of an ATREF peak of a polymer can be estimated by applying a thereference calibration of the ratio of the areas for the individual CH₃and CH₂ response (i.e. area ratio CH₃/CH₂ versus comonomer content).

The area of the peaks can be calculated using a full width/half maximum(FWHM) calculation after applying the appropriate baselines to integratethe individual signal responses from the TREF chromatogram. The fullwidth/half maximum calculation is based on the ratio of methyl tomethylene response area [CH₃/CH₂] from the ATREF infra-red detector,wherein the tallest (highest) peak is identified from the base line, andthen the FWHM area is determined. For a distribution measured using anATREF peak, the FWHM area is defined as the area under the curve betweenT1 and T2, where T1 and T2 are points determined, to the left and rightof the ATREF peak, by dividing the peak height by two, and then drawinga line horizontal to the base line, that intersects the left and rightportions of the ATREF curve.

The application of infra-red spectroscopy to measure the comonomercontent of polymers in this ATREF-infra-red method is, in principle,similar to that of GPC/FTIR systems as described in the followingreferences: Markovich, Ronald P.; Hazlitt, Lonnie G.; Smith, Linley;“Development of gel-permeation chromatography-Fourier transform infraredspectroscopy for characterization of ethylene-based polyolefincopolymers”. Polymeric Materials Science and Engineering (1991), 65,98-100.; and Deslauriers, P. J.; Rohlfing, D. C.; Shieh, E. T.;“Quantifying short chain branching microstructures in ethylene-1-olefincopolymers using size exclusion chromatography and Fourier transforminfrared spectroscopy (SEC-FTIR)”, Polymer (2002), 43, 59-170, both ofwhich are incorporated by reference herein in their entirety.

In other embodiments, the inventive ethylene/α-olefin interpolymer ischaracterized by an average block index, ABI, which is greater than zeroand up to about 1.0 and a molecular weight distribution, M_(w)/M_(n),greater than about 1.3. The average block index, ABI, is the weightaverage of the block index (“BI”) for each of the polymer fractionsobtained in preparative TREF from 20° C. and 110° C., with an incrementof 5° C.:

ABI=Σ(w _(i) BI _(i))

where BI_(i) is the block index for the ith fraction of the inventiveethylene/α-olefin interpolymer obtained in preparative TREF, and w_(i)is the weight percentage of the ith fraction.

For each polymer fraction, BI is defined by one of the two followingequations (both of which give the same BI value):

${BI} = {{\frac{{1/T_{X}} - {1/T_{XO}}}{{1/T_{A}} - {1/T_{AB}}}\mspace{14mu} {or}\mspace{14mu} {BI}} = {- \frac{{LnP}_{X} - {LnP}_{XO}}{{LnP}_{A} - {LnP}_{AB}}}}$

where T_(X) is the preparative ATREF elution temperature for the ithfraction (preferably expressed in Kelvin), P_(X) is the ethylene molefraction for the ith fraction, which can be measured by NMR or IR asdescribed above. P_(AB) is the ethylene mole fraction of the wholeethylene/α-olefin interpolymer (before fractionation), which also can bemeasured by NMR or IR. T_(A) and P_(A) are the ATREF elution temperatureand the ethylene mole fraction for pure “hard segments” (which refer tothe crystalline segments of the interpolymer). As a first orderapproximation, the T_(A) and P_(A) values are set to those for highdensity polyethylene homopolymer, if the actual values for the “hardsegments” are not available. For calculations performed herein, T_(A) is372° K, P_(A) is 1.

T_(AB) is the ATREF temperature for a random copolymer of the samecomposition and having an ethylene mole fraction of P_(AB). T_(AB) canbe calculated from the following equation:

Ln P _(AB) =α/T _(AB)+β

where α and β are two constants which can be determined by calibrationusing a number of known random ethylene copolymers. It should be notedthat α and β may vary from instrument to instrument. Moreover, one wouldneed to create their own calibration curve with the polymer compositionof interest and also in a similar molecular weight range as thefractions. There is a slight molecular weight effect. If the calibrationcurve is obtained from similar molecular weight ranges, such effectwould be essentially negligible. In some embodiments, random ethylenecopolymers satisfy the following relationship:

Ln P=−237.83/T _(ATREF)+0.639

T_(XO) is the ATREF temperature for a random copolymer of the samecomposition and having an ethylene mole fraction of P_(X). T_(XO) can becalculated from LnP_(X)=α/T_(XO)+β. Conversely, P_(XO) is the ethylenemole fraction for a random copolymer of the same composition and havingan ATREF temperature of T_(X), which can be calculated from LnP_(XO)=α/T_(X)+β.

Once the block index (BI) for each preparative TREF fraction isobtained, the weight average block index, ABI, for the whole polymer canbe calculated. In some embodiments, ABI is greater than zero but lessthan about 0.3 or from about 0.1 to about 0.3. In other embodiments, ABIis greater than about 0.3 and up to about 1.0. Preferably, ABI should bein the range of from about 0.4 to about 0.7, from about 0.5 to about0.7, or from about 0.6 to about 0.9. In some embodiments, ABI is in therange of from about 0.3 to about 0.9, from about 0.3 to about 0.8, orfrom about 0.3 to about 0.7, from about 0.3 to about 0.6, from about 0.3to about 0.5, or from about 0.3 to about 0.4. In other embodiments, ABIis in the range of from about 0.4 to about 1.0, from about 0.5 to about1.0, or from about 0.6 to about 1.0, from about 0.7 to about 1.0, fromabout 0.8 to about 1.0, or from about 0.9 to about 1.0.

Another characteristic of the inventive ethylene/α-olefin interpolymeris that the inventive ethylene/α-olefin interpolymer comprises at leastone polymer fraction which can be obtained by preparative TREF, whereinthe fraction has a block index greater than about 0.1 and up to about1.0 and a molecular weight distribution, M_(w)/M_(n), greater than about1.3. In some embodiments, the polymer fraction has a block index greaterthan about 0.6 and up to about 1.0, greater than about 0.7 and up toabout 1.0, greater than about 0.8 and up to about 1.0, or greater thanabout 0.9 and up to about 1.0. In other embodiments, the polymerfraction has a block index greater than about 0.1 and up to about 1.0,greater than about 0.2 and up to about 1.0, greater than about 0.3 andup to about 1.0, greater than about 0.4 and up to about 1.0, or greaterthan about 0.4 and up to about 1.0. In still other embodiments, thepolymer fraction has a block index greater than about 0.1 and up toabout 0.5, greater than about 0.2 and up to about 0.5, greater thanabout 0.3 and up to about 0.5, or greater than about 0.4 and up to about0.5. In yet other embodiments, the polymer fraction has a block indexgreater than about 0.2 and up to about 0.9, greater than about 0.3 andup to about 0.8, greater than about 0.4 and up to about 0.7, or greaterthan about 0.5 and up to about 0.6.

For copolymers of ethylene and an α-olefin, the inventive polymerspreferably possess (1) a PDI of at least 1.3, more preferably at least1.5, at least 1.7, or at least 2.0, and most preferably at least 2.6, upto a maximum value of 5.0, more preferably up to a maximum of 3.5, andespecially up to a maximum of 2.7; (2) a heat of fusion of 80 J/g orless; (3) an ethylene content of at least 50 weight percent; (4) a glasstransition temperature, T_(g), of less than −25° C., more preferablyless than −30° C., and/or (5) one and only one T_(m).

Further, the inventive polymers can have, alone or in combination withany other properties disclosed herein, a storage modulus, G′, such thatlog(G′) is greater than or equal to 400 kPa, preferably greater than orequal to 1.0 MPa, at a temperature of 100° C. Moreover, the inventivepolymers possess a relatively flat storage modulus as a function oftemperature in the range from 0 to 100° C. (illustrated in FIG. 6) thatis characteristic of block copolymers, and heretofore unknown for anolefin copolymer, especially a copolymer of ethylene and one or moreC₃₋₈ aliphatic α-olefins. (By the term “relatively flat” in this contextis meant that log G′ (in Pascals) decreases by less than one order ofmagnitude between 50 and 100° C., preferably between 0 and 100° C.).

The inventive interpolymers may be further characterized by athermomechanical analysis penetration depth of 1 mm at a temperature ofat least 90° C. as well as a flexural modulus of from 3 kpsi (20 MPa) to13 kpsi (90 MPa). Alternatively, the inventive interpolymers can have athermomechanical analysis penetration depth of 1 mm at a temperature ofat least 104° C. as well as a flexural modulus of at least 3 kpsi (20MPa). They may be characterized as having an abrasion resistance (orvolume loss) of less than 90 mm³. FIG. 7 shows the TMA (1 mm) versusflex modulus for the inventive polymers, as compared to other knownpolymers. The inventive polymers have significantly betterflexibility-heat resistance balance than the other polymers.

Additionally, the ethylene/α-olefin interpolymers can have a melt index,12, from 0.01 to 2000 g/10 minutes, preferably from 0.01 to 1000 g/10minutes, more preferably from 0.01 to 500 g/10 minutes, and especiallyfrom 0.01 to 100 g/10 minutes. In certain embodiments, theethylene/α-olefin interpolymers have a melt index, 12, from 0.01 to 10g/10 minutes, from 0.5 to 50 g/10 minutes, from 1 to 30 g/10 minutes,from 1 to 6 g/10 minutes or from 0.3 to 10 g/10 minutes. In certainembodiments, the melt index for the ethylene/α-olefin polymers is 1 g/10minutes, 3 g/10 minutes or 5 g/10 minutes.

The polymers can have molecular weights, M_(w), from 1,000 g/mole to5,000,000 g/mole, preferably from 1000 g/mole to 1,000,000, morepreferably from 10,000 g/mole to 500,000 g/mole, and especially from10,000 g/mole to 300,000 g/mole. The density of the inventive polymerscan be from 0.80 to 0.99 g/cm³ and preferably for ethylene containingpolymers from 0.85 g/cm³ to 0.97 g/cm³. In certain embodiments, thedensity of the ethylene/α-olefin polymers ranges from 0.860 to 0.925g/cm³ or 0.867 to 0.910 g/cm³.

The process of making the polymers has been disclosed in the followingpatent applications: U.S. Provisional Application No. 60/553,906, filedMar. 17, 2004; U.S. Provisional Application No. 60/662,937, filed Mar.17, 2005; U.S. Provisional Application No. 60/662,939, filed Mar. 17,2005; U.S. Provisional Application No. 60/566,2938, filed Mar. 17, 2005;PCT Application No. PCT/US2005/008916, filed Mar. 17, 2005; PCTApplication No. PCT/US2005/008915, filed Mar. 17, 2005; and PCTApplication No. PCT/US2005/008917, filed Mar. 17, 2005, all of which areincorporated by reference herein in their entirety. For example, onesuch method comprises contacting ethylene and optionally one or moreaddition polymerizable monomers other than ethylene under additionpolymerization conditions with a catalyst composition comprising:

the admixture or reaction product resulting from combining:

(A) a first olefin polymerization catalyst having a high comonomerincorporation index,

(B) a second olefin polymerization catalyst having a comonomerincorporation index less than 90 percent, preferably less than 50percent, most preferably less than 5 percent of the comonomerincorporation index of catalyst (A), and

(C) a chain shuttling agent.

Representative catalysts and chain shuttling agent are as follows.

Catalyst (A1) is[N-(2,6-di(1-methylethyl)phenyl)amido)(2-isopropylphenyl)(α-naphthalen-2-diyl(6-pyridin-2-diyl)methane)]hafniumdimethyl, prepared according to the teachings of WO 03/40195,2003US0204017, U.S. Ser. No. 10/429,024, filed May 2, 2003, and WO04/24740.

Catalyst (A2) is[N-(2,6-di(1-methylethyl)phenyl)amido)(2-methylphenyl)(1,2-phenylene-(6-pyridin-2-diyl)methane)]hafniumdimethyl, prepared according to the teachings of WO 03/40195,2003US0204017, U.S. Ser. No. 10/429,024, filed May 2, 2003, and WO04/24740.

Catalyst (A3) isbis[N,N′″-(2,4,6-tri(methylphenyl)amido)ethylenediamine]hafniumdibenzyl.

Catalyst (A4) isbis((2-oxoyl-3-(dibenzo-1H-pyrrole-1-yl)-5-(methyl)phenyl)-2-phenoxymethyl)cyclohexane-1,2-diylzirconium (IV) dibenzyl, prepared substantially according to theteachings of US-A-2004/0010103.

Catalyst (B1) is1,2-bis-(3,5-di-t-butylphenylene)(1-(N-(1-methylethyl)immino)methyl)(2-oxoyl)zirconiumdibenzyl

Catalyst (B2) is1,2-bis-(3,5-di-t-butylphenylene)(1-1-(2-methylcyclohexyl)-immino)methyl)(2-oxoyl)zirconiumdibenzyl

Catalyst (C1) is(t-butylamido)dimethyl(3-N-pyrrolyl-1,2,3,3a,7α-η-inden-1-yl)silanetitaniumdimethyl prepared substantially according to the techniques of U.S. Pat.No. 6,268,444:

Catalyst (C2) is(t-butylamido)di(4-methylphenyl)(2-methyl-1,2,3,3a,7a-η-inden-1-yl)silanetitaniumdimethyl prepared substantially according to the teachings ofUS-A-2003/004286:

Catalyst (C3) is(t-butylamido)di(4-methylphenyl)(2-methyl-1,2,3,3a,8a-η-s-indacen-1-yl)silanetitaniumdimethyl prepared substantially according to the teachings ofUS-A-2003/004286:

Catalyst (D1) is bis(dimethyldisiloxane)(indene-1-yl)zirconiumdichloride available from Sigma-Aldrich:

Shuttling Agents The shuttling agents employed include diethylzinc,di(i-butyl)zinc, di(n-hexyl)zinc, triethylaluminum, trioctylaluminum,triethylgallium, i-butylaluminum bis(dimethyl(t-butyl)siloxane),i-butylaluminum bis(di(trimethylsilyl)amide), n-octylaluminumdi(pyridine-2-methoxide), bis(n-octadecyl), i-butylaluminum,i-butylaluminum bis(di(n-pentyl)amide), n-octylaluminumbis(2,6-di-t-butylphenoxide, n-octylaluminum di(ethyl(1-naphthyl)amide),ethylaluminum bis(t-butyldimethylsiloxide), ethylaluminumdi(bis(trimethylsilyl)amide), ethylaluminumbis(2,3,6,7-dibenzo-1-azacycloheptaneamide), n-octylaluminumbis(2,3,6,7-dibenzo-1-azacycloheptaneamide), n-octylaluminumbis(dimethyl(t-butyl)siloxide, ethylzinc (2,6-diphenylphenoxide), andethylzinc (t-butoxide).

Preferably, the foregoing process takes the form of a continuoussolution process for forming block copolymers, especially multi-blockcopolymers, preferably linear multi-block copolymers of two or moremonomers, more especially ethylene and a C₃₋₂₀ olefin or cycloolefin,and most especially ethylene and a C₄₋₂₀ α-olefin, using multiplecatalysts that are incapable of interconversion. That is, the catalystsare chemically distinct. Under continuous solution polymerizationconditions, the process is ideally suited for polymerization of mixturesof monomers at high monomer conversions. Under these polymerizationconditions, shuttling from the chain shuttling agent to the catalystbecomes advantaged compared to chain growth, and multi-block copolymers,especially linear multi-block copolymers are formed in high efficiency.

The inventive interpolymers may be differentiated from conventional,random copolymers, physical blends of polymers, and block copolymersprepared via sequential monomer addition, fluxional catalysts, anionicor cationic living polymerization techniques. In particular, compared toa random copolymer of the same monomers and monomer content atequivalent crystallinity or modulus, the inventive interpolymers havebetter (higher) heat resistance as measured by melting point, higher TMApenetration temperature, higher high-temperature tensile strength,and/or higher high-temperature torsion storage modulus as determined bydynamic mechanical analysis. Compared to a random copolymer containingthe same monomers and monomer content, the inventive interpolymers havelower compression set, particularly at elevated temperatures, lowerstress relaxation, higher creep resistance, higher tear strength, higherblocking resistance, faster setup due to higher crystallization(solidification) temperature, higher recovery (particularly at elevatedtemperatures), better abrasion resistance, higher retractive force, andbetter oil and filler acceptance.

The inventive interpolymers also exhibit a unique crystallization andbranching distribution relationship. That is, the inventiveinterpolymers have a relatively large difference between the tallestpeak temperature measured using CRYSTAF and DSC as a function of heat offusion, especially as compared to random copolymers containing the samemonomers and monomer level or physical blends of polymers, such as ablend of a high density polymer and a lower density copolymer, atequivalent overall density. It is believed that this unique feature ofthe inventive interpolymers is due to the unique distribution of thecomonomer in blocks within the polymer backbone. In particular, theinventive interpolymers may comprise alternating blocks of differingcomonomer content (including homopolymer blocks). The inventiveinterpolymers may also comprise a distribution in number and/or blocksize of polymer blocks of differing density or comonomer content, whichis a Schultz-Flory type of distribution. In addition, the inventiveinterpolymers also have a unique peak melting point and crystallizationtemperature profile that is substantially independent of polymerdensity, modulus, and morphology. In a preferred embodiment, themicrocrystalline order of the polymers demonstrates characteristicspherulites and lamellae that are distinguishable from random or blockcopolymers, even at PDI values that are less than 1.7, or even less than1.5, down to less than 1.3.

Moreover, the inventive interpolymers may be prepared using techniquesto influence the degree or level of blockiness. That is the amount ofcomonomer and length of each polymer block or segment can be altered bycontrolling the ratio and type of catalysts and shuttling agent as wellas the temperature of the polymerization, and other polymerizationvariables. A surprising benefit of this phenomenon is the discovery thatas the degree of blockiness is increased, the optical properties, tearstrength, and high temperature recovery properties of the resultingpolymer are improved. In particular, haze decreases while clarity, tearstrength, and high temperature recovery properties increase as theaverage number of blocks in the polymer increases. By selectingshuttling agents and catalyst combinations having the desired chaintransferring ability (high rates of shuttling with low levels of chaintermination) other forms of polymer termination are effectivelysuppressed. Accordingly, little if any β-hydride elimination is observedin the polymerization of ethylene/α-olefin comonomer mixtures accordingto embodiments of the invention, and the resulting crystalline blocksare highly, or substantially completely, linear, possessing little or nolong chain branching.

Polymers with highly crystalline chain ends can be selectively preparedin accordance with embodiments of the invention. In elastomerapplications, reducing the relative quantity of polymer that terminateswith an amorphous block reduces the intermolecular dilutive effect oncrystalline regions. This result can be obtained by choosing chainshuttling agents and catalysts having an appropriate response tohydrogen or other chain terminating agents. Specifically, if thecatalyst which produces highly crystalline polymer is more susceptibleto chain termination (such as by use of hydrogen) than the catalystresponsible for producing the less crystalline polymer segment (such asthrough higher comonomer incorporation, regio-error, or atactic polymerformation), then the highly crystalline polymer segments willpreferentially populate the terminal portions of the polymer. Not onlyare the resulting terminated groups crystalline, but upon termination,the highly crystalline polymer forming catalyst site is once againavailable for reinitiation of polymer formation. The initially formedpolymer is therefore another highly crystalline polymer segment.Accordingly, both ends of the resulting multi-block copolymer arepreferentially highly crystalline.

The ethylene α-olefin interpolymers used in the embodiments of theinvention are preferably interpolymers of ethylene with at least oneC₃-C₂₀ α-olefin. Copolymers of ethylene and a C₃-C₂₀ α-olefin areespecially preferred. The interpolymers may further comprise C4-C₁₈diolefin and/or alkenylbenzene. Suitable unsaturated comonomers usefulfor polymerizing with ethylene include, for example, ethylenicallyunsaturated monomers, conjugated or nonconjugated dienes, polyenes,alkenylbenzenes, etc. Examples of such comonomers include C₃-C₂₀α-olefins such as propylene, isobutylene, 1-butene, 1-hexene, 1-pentene,4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, and thelike. 1-Butene and 1-octene are especially preferred. Other suitablemonomers include styrene, halo- or alkyl-substituted styrenes,vinylbenzocyclobutane, 1,4-hexadiene, 1,7-octadiene, and naphthenics(e.g., cyclopentene, cyclohexene and cyclooctene).

While ethylene/α-olefin interpolymers are preferred polymers, otherethylene/olefin polymers may also be used. Olefins as used herein referto a family of unsaturated hydrocarbon-based compounds with at least onecarbon-carbon double bond. Depending on the selection of catalysts, anyolefin may be used in embodiments of the invention. Preferably, suitableolefins are C₃-C₂₀ aliphatic and aromatic compounds containing vinylicunsaturation, as well as cyclic compounds, such as cyclobutene,cyclopentene, dicyclopentadiene, and norbornene, including but notlimited to, norbornene substituted in the 5 and 6 position with C₁-C₂₀hydrocarbyl or cyclohydrocarbyl groups. Also included are mixtures ofsuch olefins as well as mixtures of such olefins with C₄-C₄₀ diolefincompounds.

Examples of olefin monomers include, but are not limited to propylene,isobutylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene,1-nonene, 1-decene, and 1-dodecene, 1-tetradecene, 1-hexadecene,1-octadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene,4-methyl-1-pentene, 4,6-dimethyl-1-heptene, 4-vinylcyclohexene,vinylcyclohexane, norbornadiene, ethylidene norbornene, cyclopentene,cyclohexene, dicyclopentadiene, cyclooctene, C₄-C₄₀ dienes, includingbut not limited to 1,3-butadiene, 1,3-pentadiene, 1,4-hexadiene,1,5-hexadiene, 1,7-octadiene, 1,9-decadiene, other C₄-C₄₀ α-olefins, andthe like. In certain embodiments, the α-olefin is propylene, 1-butene,1-pentene, 1-hexene, 1-octene or a combination thereof. Although anyhydrocarbon containing a vinyl group potentially may be used inembodiments of the invention, practical issues such as monomeravailability, cost, and the ability to conveniently remove unreactedmonomer from the resulting polymer may become more problematic as themolecular weight of the monomer becomes too high.

The polymerization processes described herein are well suited for theproduction of olefin polymers comprising monovinylidene aromaticmonomers including styrene, o-methyl styrene, p-methyl styrene,t-butylstyrene, and the like. In particular, interpolymers comprisingethylene and styrene can be prepared by following the teachings herein.Optionally, copolymers comprising ethylene, styrene and a C₃-C₂₀ alphaolefin, optionally comprising a C₄-C₂₀ diene, having improved propertiescan be prepared.

Suitable non-conjugated diene monomers can be a straight chain, branchedchain or cyclic hydrocarbon diene having from 6 to 15 carbon atoms.Examples of suitable non-conjugated dienes include, but are not limitedto, straight chain acyclic dienes, such as 1,4-hexadiene, 1,6-octadiene,1,7-octadiene, 1,9-decadiene, branched chain acyclic dienes, such as5-methyl-1,4-hexadiene; 3,7-dimethyl-1,6-octadiene;3,7-dimethyl-1,7-octadiene and mixed isomers of dihydromyricene anddihydroocinene, single ring alicyclic dienes, such as1,3-cyclopentadiene; 1,4-cyclohexadiene; 1,5-cyclooctadiene and1,5-cyclododecadiene, and multi-ring alicyclic fused and bridged ringdienes, such as tetrahydroindene, methyl tetrahydroindene,dicyclopentadiene, bicyclo-(2,2,1)-hepta-2,5-diene; alkenyl, alkylidene,cycloalkenyl and cycloalkylidene norbornenes, such as5-methylene-2-norbornene (MNB); 5-propenyl-2-norbornene,5-isopropylidene-2-norbornene, 5-(4-cyclopentenyl)-2-norbornene,5-cyclohexylidene-2-norbornene, 5-vinyl-2-norbornene, and norbornadiene.Of the dienes typically used to prepare EPDMs, the particularlypreferred dienes are 1,4-hexadiene (HD), 5-ethylidene-2-norbornene(ENB), 5-vinylidene-2-norbornene (VNB), 5-methylene-2-norbornene (MNB),and dicyclopentadiene (DCPD). The especially preferred dienes are5-ethylidene-2-norbornene (ENB) and 1,4-hexadiene (HD).

One class of desirable polymers that can be made in accordance withembodiments of the invention are elastomeric interpolymers of ethylene,a C₃-C₂₀ α-olefin, especially propylene, and optionally one or morediene monomers. Preferred α-olefins for use in this embodiment of thepresent invention are designated by the formula CH₂═CHR*, where R* is alinear or branched alkyl group of from 1 to 12 carbon atoms. Examples ofsuitable α-olefins include, but are not limited to, propylene,isobutylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and1-octene. A particularly preferred α-olefin is propylene. The propylenebased polymers are generally referred to in the art as EP or EPDMpolymers. Suitable dienes for use in preparing such polymers, especiallymulti-block EPDM type polymers include conjugated or non-conjugated,straight or branched chain-, cyclic- or polycyclic-dienes comprisingfrom 4 to 20 carbons. Preferred dienes include 1,4-pentadiene,1,4-hexadiene, 5-ethylidene-2-norbornene, dicyclopentadiene,cyclohexadiene, and 5-butylidene-2-norbornene. A particularly preferreddiene is 5-ethylidene-2-norbornene.

Because the diene containing polymers comprise alternating segments orblocks containing greater or lesser quantities of the diene (includingnone) and α-olefin (including none), the total quantity of diene andα-olefin may be reduced without loss of subsequent polymer properties.That is, because the diene and α-olefin monomers are preferentiallyincorporated into one type of block of the polymer rather than uniformlyor randomly throughout the polymer, they are more efficiently utilizedand subsequently the crosslink density of the polymer can be bettercontrolled. Such crosslinkable elastomers and the cured products haveadvantaged properties, including higher tensile strength and betterelastic recovery.

In some embodiments, the inventive interpolymers made with two catalystsincorporating differing quantities of comonomer have a weight ratio ofblocks formed thereby from 95:5 to 5:95. The elastomeric polymersdesirably have an ethylene content of from 20 to 90 percent, a dienecontent of from 0.1 to 10 percent, and an α-olefin content of from 10 to80 percent, based on the total weight of the polymer. Furtherpreferably, the multi-block elastomeric polymers have an ethylenecontent of from 60 to 90 percent, a diene content of from 0.1 to 10percent, and an α-olefin content of from 10 to 40 percent, based on thetotal weight of the polymer. Preferred polymers are high molecularweight polymers, having a weight average molecular weight (Mw) from10,000 to about 2,500,000, preferably from 20,000 to 500,000, morepreferably from 20,000 to 350,000, and a polydispersity less than 3.5,more preferably less than 3.0, and a Mooney viscosity (ML (1+4) 125° C.)from 1 to 250. More preferably, such polymers have an ethylene contentfrom 65 to 75 percent, a diene content from 0 to 6 percent, and anα-olefin content from 20 to 35 percent.

The ethylene/α-olefin interpolymers can be functionalized byincorporating at least one functional group in its polymer structure.Exemplary functional groups may include, for example, ethylenicallyunsaturated mono- and di-functional carboxylic acids, ethylenicallyunsaturated mono- and di-functional carboxylic acid anhydrides, saltsthereof and esters thereof. Such functional groups may be grafted to anethylene/α-olefin interpolymer, or it may be copolymerized with ethyleneand an optional additional comonomer to form an interpolymer ofethylene, the functional comonomer and optionally other comonomer(s).Means for grafting functional groups onto polyethylene are described forexample in U.S. Pat. Nos. 4,762,890, 4,927,888, and 4,950,541, thedisclosures of these patents are incorporated herein by reference intheir entirety. One particularly useful functional group is malicanhydride.

The amount of the functional group present in the functionalinterpolymer can vary. The functional group can typically be present ina copolymer-type functionalized interpolymer in an amount of at leastabout 1.0 weight percent, preferably at least about 5 weight percent,and more preferably at least about 7 weight percent. The functionalgroup will typically be present in a copolymer-type functionalizedinterpolymer in an amount less than about 40 weight percent, preferablyless than about 30 weight percent, and more preferably less than about25 weight percent.

Testing Methods

In the examples that follow, the following analytical techniques areemployed:

GPC Method for Samples 1-4 and A-C

An automated liquid-handling robot equipped with a heated needle set to160° C. is used to add enough 1,2,4-trichlorobenzene stabilized with 300ppm Ionol to each dried polymer sample to give a final concentration of30 mg/mL. A small glass stir rod is placed into each tube and thesamples are heated to 160° C. for 2 hours on a heated, orbital-shakerrotating at 250 rpm. The concentrated polymer solution is then dilutedto 1 mg/ml using the automated liquid-handling robot and the heatedneedle set to 160° C.

A Symyx Rapid GPC system is used to determine the molecular weight datafor each sample. A Gilson 350 pump set at 2.0 ml/min flow rate is usedto pump helium-purged 1,2-dichlorobenzene stabilized with 300 ppm Ionolas the mobile phase through three Plgel 10 micrometer (μm) Mixed B 300mm×7.5 mm columns placed in series and heated to 160° C. A Polymer LabsELS 1000 Detector is used with the Evaporator set to 250° C., theNebulizer set to 165° C., and the nitrogen flow rate set to 1.8 SLM at apressure of 60-80 psi (400-600 kPa) N₂. The polymer samples are heatedto 160° C. and each sample injected into a 250 μl loop using theliquid-handling robot and a heated needle. Serial analysis of thepolymer samples using two switched loops and overlapping injections areused. The sample data is collected and analyzed using Symyx Epoch™software. Peaks are manually integrated and the molecular weightinformation reported uncorrected against a polystyrene standardcalibration curve.

Standard CRYSTAF Method

Branching distributions are determined by crystallization analysisfractionation (CRYSTAF) using a CRYSTAF 200 unit commercially availablefrom PolymerChar, Valencia, Spain. The samples are dissolved in 1,2,4trichlorobenzene at 160° C. (0.66 mg/mL) for 1 hr and stabilized at 95°C. for 45 minutes. The sampling temperatures range from 95 to 30° C. ata cooling rate of 0.2° C./min. An infrared detector is used to measurethe polymer solution concentrations. The cumulative solubleconcentration is measured as the polymer crystallizes while thetemperature is decreased. The analytical derivative of the cumulativeprofile reflects the short chain branching distribution of the polymer.

The CRYSTAF peak temperature and area are identified by the peakanalysis module included in the CRYSTAF Software (Version 2001.b,PolymerChar, Valencia, Spain). The CRYSTAF peak finding routineidentifies a peak temperature as a maximum in the dW/dT curve and thearea between the largest positive inflections on either side of theidentified peak in the derivative curve. To calculate the CRYSTAF curve,the preferred processing parameters are with a temperature limit of 70°C. and with smoothing parameters above the temperature limit of 0.1, andbelow the temperature limit of 0.3.

DSC Standard Method (Excluding Samples 1-4 and A-C)

Differential Scanning Calorimetry results are determined using a TAImodel Q1000 DSC equipped with an RCS cooling accessory and anautosampler. A nitrogen purge gas flow of 50 ml/min is used. The sampleis pressed into a thin film and melted in the press at about 175° C. andthen air-cooled to room temperature (25° C.). 3-10 mg of material isthen cut into a 6 mm diameter disk, accurately weighed, placed in alight aluminum pan (ca 50 mg), and then crimped shut. The thermalbehavior of the sample is investigated with the following temperatureprofile. The sample is rapidly heated to 180° C. and held isothermal for3 minutes in order to remove any previous thermal history. The sample isthen cooled to −40° C. at 10° C./min cooling rate and held at −40° C.for 3 minutes. The sample is then heated to 150° C. at 10° C./min.heating rate. The cooling and second heating curves are recorded.

The DSC melting peak is measured as the maximum in heat flow rate (W/g)with respect to the linear baseline drawn between −30° C. and end ofmelting. The heat of fusion is measured as the area under the meltingcurve between −30° C. and the end of melting using a linear baseline.

GPC Method (Excluding Samples 1-4 and A-C)

The gel permeation chromatographic system consists of either a PolymerLaboratories Model PL-210 or a Polymer Laboratories Model PL-220instrument. The column and carousel compartments are operated at 140° C.Three Polymer Laboratories 10-micron Mixed-B columns are used. Thesolvent is 1,2,4 trichlorobenzene. The samples are prepared at aconcentration of 0.1 grams of polymer in 50 milliliters of solventcontaining 200 ppm of butylated hydroxytoluene (BHT). Samples areprepared by agitating lightly for 2 hours at 160° C. The injectionvolume used is 100 microliters and the flow rate is 1.0 ml/minute.

Calibration of the GPC column set is performed with 21 narrow molecularweight distribution polystyrene standards with molecular weights rangingfrom 580 to 8,400,000, arranged in 6 “cocktail” mixtures with at least adecade of separation between individual molecular weights. The standardsare purchased from Polymer Laboratories (Shropshire, UK). Thepolystyrene standards are prepared at 0.025 grams in 50 milliliters ofsolvent for molecular weights equal to or greater than 1,000,000, and0.05 grams in 50 milliliters of solvent for molecular weights less than1,000,000. The polystyrene standards are dissolved at 80° C. with gentleagitation for 30 minutes. The narrow standards mixtures are run firstand in order of decreasing highest molecular weight component tominimize degradation. The polystyrene standard peak molecular weightsare converted to polyethylene molecular weights using the followingequation (as described in Williams and Ward, J. Polym. Sci., Polym.Let., 6, 621 (1968)): M_(polyethylene)=0.431(M_(polystyrene)).

Polyethylene equivalent molecular weight calculations are performedusing Viscotek TriSEC software Version 3.0.

Compression Set

Compression set is measured according to ASTM D 395. The sample isprepared by stacking 25.4 mm diameter round discs of 3.2 mm, 2.0 mm, and0.25 mm thickness until a total thickness of 12.7 mm is reached. Thediscs are cut from 12.7 cm×12.7 cm compression molded plaques moldedwith a hot press under the following conditions: zero pressure for 3 minat 190° C., followed by 86 MPa for 2 min at 190° C., followed by coolinginside the press with cold running water at 86 MPa.

Density

Samples for density measurement are prepared according to ASTM D 1928.Measurements are made within one hour of sample pressing using ASTMD792, Method B.

Flexural/Secant Modulus/Storage Modulus

Samples are compression molded using ASTM D 1928. Flexural and 2 percentsecant moduli are measured according to ASTM D-790. Storage modulus ismeasured according to ASTM D 5026-01 or equivalent technique.

Optical Properties

Films of 0.4 mm thickness are compression molded using a hot press(Carver Model #4095-4PR1001R). The pellets are placed betweenpolytetrafluoroethylene sheets, heated at 190° C. at 55 psi (380 kPa)for 3 min, followed by 1.3 MPa for 3 min, and then 2.6 MPa for 3 min.The film is then cooled in the press with running cold water at 1.3 MPafor 1 min. The compression molded films are used for opticalmeasurements, tensile behavior, recovery, and stress relaxation.

Clarity is measured using BYK Gardner Haze-gard as specified in ASTM D1746.

45° gloss is measured using BYK Gardner Glossmeter Microgloss 45° asspecified in ASTM D-2457

Internal haze is measured using BYK Gardner Haze-gard based on ASTM D1003 Procedure A. Mineral oil is applied to the film surface to removesurface scratches.

Mechanical Properties—Tensile, Hysteresis, and Tear

Stress-strain behavior in uniaxial tension is measured using ASTM D 1708microtensile specimens. Samples are stretched with an Instron at 500%min⁻¹ at 21° C. Tensile strength and elongation at break are reportedfrom an average of 5 specimens.

100% and 300% Hysteresis is determined from cyclic loading to 100% and300% strains using ASTM D 1708 microtensile specimens with an Instron™instrument. The sample is loaded and unloaded at 267% min⁻¹ for 3 cyclesat 21° C. Cyclic experiments at 300% and 80° C. are conducted using anenvironmental chamber. In the 80° C. experiment, the sample is allowedto equilibrate for 45 minutes at the test temperature before testing. Inthe 21° C., 300% strain cyclic experiment, the retractive stress at 150%strain from the first unloading cycle is recorded. Percent recovery forall experiments are calculated from the first unloading cycle using thestrain at which the load returned to the base line. The percent recoveryis defined as:

${\% \mspace{14mu} {Recovery}} = {\frac{ɛ_{f} - ɛ_{s}}{ɛ_{f}} \times 100}$

where ε_(f) is the strain taken for cyclic loading and ε_(s) is thestrain where the load returns to the baseline during the 1^(st)unloading cycle.

Stress relaxation is measured at 50 percent strain and 37° C. for 12hours using an Instron™ instrument equipped with an environmentalchamber. The gauge geometry was 76 mm×25 mm×0.4 mm. After equilibratingat 37° C. for 45 min in the environmental chamber, the sample wasstretched to 50% strain at 333% min⁻¹. Stress was recorded as a functionof time for 12 hours. The percent stress relaxation after 12 hours wascalculated using the formula:

${\% \mspace{14mu} {Stress}\mspace{14mu} {Relaxation}} = {\frac{L_{0} - L_{12}}{L_{0}} \times 100}$

where L₀ is the load at 50% strain at 0 time and L₁₂ is the load at 50percent strain after 12 hours.

Tensile notched tear experiments are carried out on samples having adensity of 0.88 g/cc or less using an Instron™ instrument. The geometryconsists of a gauge section of 76 mm×13 mm×0.4 mm with a 2 mm notch cutinto the sample at half the specimen length. The sample is stretched at508 mm min⁻¹ at 21° C. until it breaks. The tear energy is calculated asthe area under the stress-elongation curve up to strain at maximum load.An average of at least 3 specimens are reported.

TMA

Thermal Mechanical Analysis (Penetration Temperature) is conducted on 30mm diameter×3.3 mm thick, compression molded discs, formed at 180° C.and 10 MPa molding pressure for 5 minutes and then air quenched. Theinstrument used is a TMA 7, brand available from Perkin-Elmer. In thetest, a probe with 1.5 mm radius tip (P/N N519-0416) is applied to thesurface of the sample disc with 1N force. The temperature is raised at5° C./min from 25° C. The probe penetration distance is measured as afunction of temperature. The experiment ends when the probe haspenetrated 1 mm into the sample.

DMA

Dynamic Mechanical Analysis (DMA) is measured on compression moldeddisks formed in a hot press at 180° C. at 10 MPa pressure for 5 minutesand then water cooled in the press at 90° C./min. Testing is conductedusing an ARES controlled strain rheometer (TA instruments) equipped withdual cantilever fixtures for torsion testing.

A 1.5 mm plaque is pressed and cut in a bar of dimensions 32×12 mm. Thesample is clamped at both ends between fixtures separated by 10 mm (gripseparation ΔL) and subjected to successive temperature steps from −100°C. to 200° C. (5° C. per step). At each temperature the torsion modulusG′ is measured at an angular frequency of 10 rad/s, the strain amplitudebeing maintained between 0.1 percent and 4 percent to ensure that thetorque is sufficient and that the measurement remains in the linearregime.

An initial static force of 10 g is maintained (auto-tension mode) toprevent slack in the sample when thermal expansion occurs. As aconsequence, the grip separation ΔL increases with the temperature,particularly above the melting or softening point of the polymer sample.The test stops at the maximum temperature or when the gap between thefixtures reaches 65 mm.

Melt Index

Melt index, or 12, is measured in accordance with ASTM D 1238, Condition190° C./2.16 kg. Melt index, or 110 is also measured in accordance withASTM D 1238, Condition 190° C./10 kg.

ATREF

Analytical temperature rising elution fractionation (ATREF) analysis isconducted according to the method described in U.S. Pat. No. 4,798,081and Wilde, L.; Ryle, T. R.; Knobeloch, D. C.; Peat, I. R.; Determinationof Branching Distributions in Polyethylene and Ethylene Copolymers, J.Polym. Sci., 20, 441-455 (1982), which are incorporated by referenceherein in their entirety. The composition to be analyzed is dissolved intrichlorobenzene and allowed to crystallize in a column containing aninert support (stainless steel shot) by slowly reducing the temperatureto 20° C. at a cooling rate of 0.1° C./min. The column is equipped withan infrared detector. An ATREF chromatogram curve is then generated byeluting the crystallized polymer sample from the column by slowlyincreasing the temperature of the eluting solvent (trichlorobenzene)from 20 to 120° C. at a rate of 1.5° C./min.

¹³C NMR Analysis

The samples are prepared by adding approximately 3 g of a 50/50 mixtureof tetrachloroethane-d²/orthodichlorobenzene to 0.4 g sample in a 10 mmNMR tube. The samples are dissolved and homogenized by heating the tubeand its contents to 150° C. The data are collected using a JEOL Eclipse™400 MHz spectrometer or a Varian Unity Plus™ 400 MHz spectrometer,corresponding to a ¹³C resonance frequency of 100.5 MHz. The data areacquired using 4000 transients per data file with a 6 second pulserepetition delay. To achieve minimum signal-to-noise for quantitativeanalysis, multiple data files are added together. The spectral width is25,000 Hz with a minimum file size of 32K data points. The samples areanalyzed at 130° C. in a 10 mm broad band probe. The comonomerincorporation is determined using Randall's triad method (Randall, J.C.; JMS-Rev. Macromol. Chem. Phys., C29, 201-317 (1989), which isincorporated by reference herein in its entirety.

Polymer Fractionation by TREF

Large-scale TREF fractionation is carried by dissolving 15-20 g ofpolymer in 2 liters of 1,2,4-trichlorobenzene (TCB) by stirring for 4hours at 160° C. The polymer solution is forced by 15 psig (100 kPa)nitrogen onto a 3 inch by 4 foot (7.6 cm×12 cm) steel column packed witha 60:40 (v:v) mix of 30-40 mesh (600-425 μm) spherical, technicalquality glass beads (available from Potters Industries, HC 30 Box 20,Brownwood, T_(X), 76801) and stainless steel, 0.028″ (0.7 mm) diametercut wire shot (available from Pellets, Inc. 63 Industrial Drive, NorthTonawanda, N.Y., 14120). The column is immersed in a thermallycontrolled oil jacket, set initially to 160° C. The column is firstcooled ballistically to 125° C., then slow cooled to 20° C. at 0.04° C.per minute and held for one hour. Fresh TCB is introduced at about 65ml/min while the temperature is increased at 0.167° C. per minute.

Approximately 2000 ml portions of eluant from the preparative TREFcolumn are collected in a 16 station, heated fraction collector. Thepolymer is concentrated in each fraction using a rotary evaporator untilabout 50 to 100 ml of the polymer solution remains. The concentratedsolutions are allowed to stand overnight before adding excess methanol,filtering, and rinsing (approx. 300-500 ml of methanol including thefinal rinse). The filtration step is performed on a 3 position vacuumassisted filtering station using 5.0 μm polytetrafluoroethylene coatedfilter paper (available from Osmonics Inc., Cat# Z50WP04750). Thefiltrated fractions are dried overnight in a vacuum oven at 60° C. andweighed on an analytical balance before further testing.

Melt Strength

Melt Strength (MS) is measured by using a capillary rheometer fittedwith a 2.1 mm diameter, 20:1 die with an entrance angle of approximately45 degrees. After equilibrating the samples at 190° C. for 10 minutes,the piston is run at a speed of 1 inch/minute (2.54 cm/minute). Thestandard test temperature is 190° C. The sample is drawn uniaxially to aset of accelerating nips located 100 mm below the die with anacceleration of 2.4 mm/sec². The required tensile force is recorded as afunction of the take-up speed of the nip rolls. The maximum tensileforce attained during the test is defined as the melt strength. In thecase of polymer melt exhibiting draw resonance, the tensile force beforethe onset of draw resonance was taken as melt strength. The meltstrength is recorded in centiNewtons (“cN”).

Catalysts

The term “overnight”, if used, refers to a time of approximately 16-18hours, the term “room temperature”, refers to a temperature of 20-25°C., and the term “mixed alkanes” refers to a commercially obtainedmixture of C₆₋₉ aliphatic hydrocarbons available under the tradedesignation Isopar E®, from ExxonMobil Chemical Company. In the eventthe name of a compound herein does not conform to the structuralrepresentation thereof, the structural representation shall control. Thesynthesis of all metal complexes and the preparation of all screeningexperiments were carried out in a dry nitrogen atmosphere using dry boxtechniques. All solvents used were HPLC grade and were dried beforetheir use.

MMAO refers to modified methylalumoxane, a triisobutylaluminum modifiedmethylalumoxane available commercially from Akzo-Noble Corporation.

The preparation of catalyst (B1) is conducted as follows.

a) Preparation of(1-methylethyl)(2-hydroxy-3,5-di(t-butyl)phenyl)methylimine

3,5-Di-t-butylsalicylaldehyde (3.00 g) is added to 10 mL ofisopropylamine. The solution rapidly turns bright yellow. After stirringat ambient temperature for 3 hours, volatiles are removed under vacuumto yield a bright yellow, crystalline solid (97 percent yield).

b) Preparation of1,2-bis-(3,5-di-t-butylphenylene)(1-N-(1-methylethyl)immino)methyl)(2-oxoyl)zirconium dibenzyl

A solution of (1-methylethyl)(2-hydroxy-3,5-di(t-butyl)phenyl)imine (605mg, 2.2 mmol) in 5 mL toluene is slowly added to a solution ofZr(CH₂Ph)₄ (500 mg, 1.1 mmol) in 50 mL toluene. The resulting darkyellow solution is stirred for 30 min. Solvent is removed under reducedpressure to yield the desired product as a reddish-brown solid.

The preparation of catalyst (B2) is conducted as follows.

a) Preparation of(1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)imine

2-Methylcyclohexylamine (8.44 mL, 64.0 mmol) is dissolved in methanol(90 mL), and di-t-butylsalicaldehyde (10.00 g, 42.67 mmol) is added. Thereaction mixture is stirred for three hours and then cooled to −25° C.for 12 hrs. The resulting yellow solid precipitate is collected byfiltration and washed with cold methanol (2×15 mL), and then dried underreduced pressure. The yield is 11.17 g of a yellow solid. ¹H NMR isconsistent with the desired product as a mixture of isomers.

b) Preparation ofbis-(1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)immino)zirconiumdibenzyl

A solution of(1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)imine (7.63g, 23.2 mmol) in 200 mL toluene is slowly added to a solution ofZr(CH₂Ph)₄ (5.28 g, 11.6 mmol) in 600 mL toluene. The resulting darkyellow solution is stirred for 1 hour at 25° C. The solution is dilutedfurther with 680 mL toluene to give a solution having a concentration of0.00783 M.

Cocatalyst 1 A mixture of methyldi(C₁₄₋₁₈ alkyl)ammonium salts oftetrakis(pentafluorophenyl)borate (here-in-after armeenium borate),prepared by reaction of a long chain trialkylamine (Armeen™ M2HT,available from Akzo-Nobel, Inc.), HCl and Li[B(C₆F₅)₄], substantially asdisclosed in U.S. Pat. No. 5,919,9883, Ex. 2.

Cocatalyst 2 Mixed C₁₄₋₁₈ alkyldimethylammonium salt ofbis(tris(pentafluorophenyl)-alumane)-2-undecylimidazolide, preparedaccording to U.S. Pat. No. 6,395,671, Ex. 16.

Shuttling Agents The shuttling agents employed include diethylzinc (DEZ,SA1), di(i-butyl)zinc (SA2), di(n-hexyl)zinc (SA3), triethylaluminum(TEA, SA4), trioctylaluminum (SA5), triethylgallium (SA6),i-butylaluminum bis(dimethyl(t-butyl)siloxane) (SA7), i-butylaluminumbis(di(trimethylsilyl)amide) (SA8), n-octylaluminumdi(pyridine-2-methoxide) (SA9), bis(n-octadecyl)_(i)-butylaluminum(SA10), i-butylaluminum bis(di(n-pentyl)amide) (SA 11), n-octylaluminumbis(2,6-di-t-butylphenoxide) (SA12), n-octylaluminumdi(ethyl(1-naphthyl)amide) (SA 13), ethylaluminumbis(t-butyldimethylsiloxide) (SA 14), ethylaluminumdi(bis(trimethylsilyl)amide) (SA 15), ethylaluminumbis(2,3,6,7-dibenzo-1-azacycloheptaneamide) (SA 16), n-octylaluminumbis(2,3,6,7-dibenzo-1-azacycloheptaneamide) (SA 17), n-octylaluminumbis(dimethyl(t-butyl)siloxide(SA 18), ethylzinc (2,6-diphenylphenoxide)(SA 19), and ethylzinc (t-butoxide) (SA20).

Examples 1-4 Comparative A-C General High Throughput ParallelPolymerization Conditions

Polymerizations are conducted using a high throughput, parallelpolymerization reactor (PPR) available from Symyx technologies, Inc. andoperated substantially according to U.S. Pat. Nos. 6,248,540, 6,030,917,6,362,309, 6,306,658, and 6,316,663. Ethylene copolymerizations areconducted at 130° C. and 200 psi (1.4 MPa) with ethylene on demand using1.2 equivalents of cocatalyst 1 based on total catalyst used (1.1equivalents when MMAO is present). A series of polymerizations areconducted in a parallel pressure reactor (PPR) contained of 48individual reactor cells in a 6×8 array that are fitted with apre-weighed glass tube. The working volume in each reactor cell is 6000μL. Each cell is temperature and pressure controlled with stirringprovided by individual stirring paddles. The monomer gas and quench gasare plumbed directly into the PPR unit and controlled by automaticvalves. Liquid reagents are robotically added to each reactor cell bysyringes and the reservoir solvent is mixed alkanes. The order ofaddition is mixed alkanes solvent (4 ml), ethylene, 1-octene comonomer(1 ml), cocatalyst 1 or cocatalyst 1/MMAO mixture, shuttling agent, andcatalyst or catalyst mixture. When a mixture of cocatalyst 1 and MMAO ora mixture of two catalysts is used, the reagents are premixed in a smallvial immediately prior to addition to the reactor. When a reagent isomitted in an experiment, the above order of addition is otherwisemaintained. Polymerizations are conducted for approximately 1-2 minutes,until predetermined ethylene consumptions are reached. After quenchingwith CO, the reactors are cooled and the glass tubes are unloaded. Thetubes are transferred to a centrifuge/vacuum drying unit, and dried for12 hours at 60° C. The tubes containing dried polymer are weighed andthe difference between this weight and the tare weight gives the netyield of polymer. Results are contained in Table 1. In Table 1 andelsewhere in the application, comparative compounds are indicated by anasterisk (*).

Examples 1-4 demonstrate the synthesis of linear block copolymers by thepresent invention as evidenced by the formation of a very narrow MWD,essentially monomodal copolymer when DEZ is present and a bimodal, broadmolecular weight distribution product (a mixture of separately producedpolymers) in the absence of DEZ. Due to the fact that Catalyst (A1) isknown to incorporate more octene than Catalyst (B1), the differentblocks or segments of the resulting copolymers of the invention aredistinguishable based on branching or density.

TABLE 1 Cat. (A1) Cat (B1) Cocat MMAO shuttling Ex. (μmol) (μmol) (μmol)(μmol) agent (μmol) Yield (g) Mn Mw/Mn hexyls¹ A* 0.06 — 0.066 0.3 —0.1363 300502 3.32 — B* — 0.1 0.110 0.5 — 0.1581 36957 1.22 2.5 C* 0.060.1 0.176 0.8 — 0.2038 45526 5.30² 5.5 1 0.06 0.1 0.192 — DEZ (8.0)0.1974 28715 1.19 4.8 2 0.06 0.1 0.192 — DEZ (80.0) 0.1468 2161 1.1214.4 3 0.06 0.1 0.192 — TEA (8.0) 0.208 22675 1.71 4.6 4 0.06 0.1 0.192— TEA (80.0) 0.1879 3338 1.54 9.4 ¹C₆ or higher chain content per 1000carbons ²Bimodal molecular weight distribution

It may be seen the polymers produced according to the invention have arelatively narrow polydispersity (Mw/Mn) and larger block-copolymercontent (trimer, tetramer, or larger) than polymers prepared in theabsence of the shuttling agent.

Further characterizing data for the polymers of Table 1 are determinedby reference to the figures. More specifically DSC and ATREF resultsshow the following:

The DSC curve for the polymer of example 1 shows a 115.7° C. meltingpoint (Tm) with a heat of fusion of 158.1 J/g. The corresponding CRYSTAFcurve shows the tallest peak at 34.5° C. with a peak area of 52.9percent. The difference between the DSC Tm and the Tcrystaf is 81.2° C.

The DSC curve for the polymer of example 2 shows a peak with a 109.7° C.melting point (Tm) with a heat of fusion of 214.0 J/g. The correspondingCRYSTAF curve shows the tallest peak at 46.2° C. with a peak area of57.0 percent. The difference between the DSC Tm and the Tcrystaf is63.5° C.

The DSC curve for the polymer of example 3 shows a peak with a 120.7° C.melting point (Tm) with a heat of fusion of 160.1 J/g. The correspondingCRYSTAF curve shows the tallest peak at 66.1° C. with a peak area of71.8 percent. The difference between the DSC Tm and the Tcrystaf is54.6° C.

The DSC curve for the polymer of example 4 shows a peak with a 104.5° C.melting point (Tm) with a heat of fusion of 170.7 J/g. The correspondingCRYSTAF curve shows the tallest peak at 30° C. with a peak area of 18.2percent. The difference between the DSC Tm and the Tcrystaf is 74.5° C.

The DSC curve for comparative A shows a 90.0° C. melting point (Tm) witha heat of fusion of 86.7 J/g. The corresponding CRYSTAF curve shows thetallest peak at 48.5° C. with a peak area of 29.4 percent. Both of thesevalues are consistent with a resin that is low in density. Thedifference between the DSC Tm and the Tcrystaf is 41.8° C.

The DSC curve for comparative B shows a 129.8° C. melting point (Tm)with a heat of fusion of 237.0 J/g. The corresponding CRYSTAF curveshows the tallest peak at 82.4° C. with a peak area of 83.7 percent.Both of these values are consistent with a resin that is high indensity. The difference between the DSC Tm and the Tcrystaf is 47.4° C.

The DSC curve for comparative C shows a 125.3° C. melting point (Tm)with a heat of fusion of 143.0 J/g. The corresponding CRYSTAF curveshows the tallest peak at 81.8° C. with a peak area of 34.7 percent aswell as a lower crystalline peak at 52.4° C. The separation between thetwo peaks is consistent with the presence of a high crystalline and alow crystalline polymer. The difference between the DSC Tm and theTcrystaf is 43.5° C.

Examples 5-19 Comparatives D-F, Continuous Solution Polymerization,Catalyst A1/B2+DEZ

Continuous solution polymerizations are carried out in a computercontrolled autoclave reactor equipped with an internal stirrer. Purifiedmixed alkanes solvent (Isopar™ E available from ExxonMobil ChemicalCompany), ethylene at 2.70 lbs/hour (1.22 kg/hour), 1-octene, andhydrogen (where used) are supplied to a 3.8 L reactor equipped with ajacket for temperature control and an internal thermocouple. The solventfeed to the reactor is measured by a mass-flow controller. A variablespeed diaphragm pump controls the solvent flow rate and pressure to thereactor. At the discharge of the pump, a side stream is taken to provideflush flows for the catalyst and cocatalyst 1 injection lines and thereactor agitator. These flows are measured by Micro-Motion mass flowmeters and controlled by control valves or by the manual adjustment ofneedle valves. The remaining solvent is combined with 1-octene,ethylene, and hydrogen (where used) and fed to the reactor. A mass flowcontroller is used to deliver hydrogen to the reactor as needed. Thetemperature of the solvent/monomer solution is controlled by use of aheat exchanger before entering the reactor. This stream enters thebottom of the reactor. The catalyst component solutions are meteredusing pumps and mass flow meters and are combined with the catalystflush solvent and introduced into the bottom of the reactor. The reactoris run liquid-full at 500 psig (3.45 MPa) with vigorous stirring.Product is removed through exit lines at the top of the reactor. Allexit lines from the reactor are steam traced and insulated.Polymerization is stopped by the addition of a small amount of waterinto the exit line along with any stabilizers or other additives andpassing the mixture through a static mixer. The product stream is thenheated by passing through a heat exchanger before devolatilization. Thepolymer product is recovered by extrusion using a devolatilizingextruder and water cooled pelletizer. Process details and results arecontained in Table 2. Selected polymer properties are provided in Table3.

TABLE 2 Process details for preparation of exemplary polymers Cat Cat A1Cat B2 DEZ Cocat Cocat Poly C₈H₁₆ Solv. H₂ T A1² Flow B2³ Flow DEZ FlowConc. Flow [C₂H₄]/ Rate⁵ Ex. kg/hr kg/hr sccm¹ ° C. ppm kg/hr ppm kg/hrConc % kg/hr ppm kg/hr [DEZ]⁴ kg/hr Conv %⁶ Solids % Eff.⁷ D* 1.63 12.729.90 120 142.2  0.14 — — 0.19 0.32  820 0.17 536 1.81 88.8 11.2 95.2 E*″ 9.5 5.00 ″ — — 109 0.10 0.19 ″ 1743 0.40 485 1.47 89.9 11.3 126.8 F* ″11.3 251.6 ″ 71.7 0.06 30.8 0.06 — — ″ 0.11 — 1.55 88.5 10.3 257.7  5 ″″ — ″ ″ 0.14 30.8 0.13 0.17 0.43 ″ 0.26 419 1.64 89.6 11.1 118.3  6 ″ ″4.92 ″ ″ 0.10 30.4 0.08 0.17 0.32 ″ 0.18 570 1.65 89.3 11.1 172.7  7 ″ ″21.70 ″ ″ 0.07 30.8 0.06 0.17 0.25 ″ 0.13 718 1.60 89.2 10.6 244.1  8 ″″ 36.90 ″ ″ 0.06 ″ ″ ″ 0.10 ″ 0.12 1778  1.62 90.0 10.8 261.1  9 ″ ″78.43 ″ ″ ″ ″ ″ ″ 0.04 ″ ″ 4596  1.63 90.2 10.8 267.9 10 ″ ″ 0.00 12371.1 0.12 30.3 0.14 0.34 0.19 1743 0.08 415 1.67 90.31 11.1 131.1 11 ″ ″″ 120 71.1 0.16 ″ 0.17 0.80 0.15 1743 0.10 249 1.68 89.56 11.1 100.6 12″ ″ ″ 121 71.1 0.15 ″ 0.07 ″ 0.09 1743 0.07 396 1.70 90.02 11.3 137.0 13″ ″ ″ 122 71.1 0.12 ″ 0.06 ″ 0.05 1743 0.05 653 1.69 89.64 11.2 161.9 14″ ″ ″ 120 71.1 0.05 ″ 0.29 ″ 0.10 1743 0.10 395 1.41 89.42 9.3 114.1 152.45 ″ ″ ″ 71.1 0.14 ″ 0.17 ″ 0.14 1743 0.09 282 1.80 89.33 11.3 121.316 ″ ″ ″ 122 71.1 0.10 ″ 0.13 ″ 0.07 1743 0.07 485 1.78 90.11 11.2 159.717 ″ ″ ″ 121 71.1 0.10 ″ 0.14 ″ 0.08 1743 ″ 506 1.75 89.08 11.0 155.6 180.69 ″ ″ 121 71.1 ″ ″ 0.22 ″ 0.11 1743 0.10 331 1.25 89.93 8.8 90.2 190.32 ″ ″ 122 71.1 0.06 ″ ″ ″ 0.09 1743 0.08 367 1.16 90.74 8.4 106.0*Comparative, not an example of the invention ¹standard cm³/min²[N-(2,6-di(1-methylethyl)phenyl)amido)(2-isopropylphenyl)(α-naphthalen-2-diyl(6-pyridin-2-diyl)methane)]hafniumdimethyl³bis-(1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)immino)zirconium dibenzyl ⁴molar ratio in reactor ⁵polymer production rate⁶percent ethylene conversion in reactor ⁷efficiency, kg polymer/g Mwhere g M = g Hf + g Zr

TABLE 3 Properties of exemplary polymers Heat of CRYSTAF Density Mw MnFusion T_(m) T_(c) T_(CRYSTAF) Tm − T_(CRYSTAF) Peak Area Ex. (g/cm³) I₂I₁₀ I₁₀/I₂ (g/mol) (g/mol) Mw/Mn (J/g) (° C.) (° C.) (° C.) (° C.)(percent) D* 0.8627 1.5 10.0 6.5 110,000 55,800 2.0 32 37 45 30 7 99 E*0.9378 7.0 39.0 5.6 65,000 33,300 2.0 183 124 113 79 45 95 F* 0.8895 0.912.5 13.4 137,300 9,980 13.8 90 125 111 78 47 20  5 0.8786 1.5 9.8 6.7104,600 53,200 2.0 55 120 101 48 72 60  6 0.8785 1.1 7.5 6.5 10960053300 2.1 55 115 94 44 71 63  7 0.8825 1.0 7.2 7.1 118,500 53,100 2.2 69121 103 49 72 29  8 0.8828 0.9 6.8 7.7 129,000 40,100 3.2 68 124 106 8043 13  9 0.8836 1.1 9.7 9.1 129600 28700 4.5 74 125 109 81 44 16 100.8784 1.2 7.5 6.5 113,100 58,200 1.9 54 116 92 41 75 52 11 0.8818 9.159.2 6.5 66,200 36,500 1.8 63 114 93 40 74 25 12 0.8700 2.1 13.2 6.4101,500 55,100 1.8 40 113 80 30 83 91 13 0.8718 0.7 4.4 6.5 132,10063,600 2.1 42 114 80 30 81 8 14 0.9116 2.6 15.6 6.0 81,900 43,600 1.9123 121 106 73 48 92 15 0.8719 6.0 41.6 6.9 79,900 40,100 2.0 33 114 9132 82 10 16 0.8758 0.5 3.4 7.1 148,500 74,900 2.0 43 117 96 48 69 65 170.8757 1.7 11.3 6.8 107,500 54,000 2.0 43 116 96 43 73 57 18 0.9192 4.124.9 6.1 72,000 37,900 1.9 136 120 106 70 50 94 19 0.9344 3.4 20.3 6.076,800 39,400 1.9 169 125 112 80 45 88

The resulting polymers are tested by DSC and ATREF as with previousexamples. Results are as follows:

The DSC curve for the polymer of example 5 shows a peak with a 119.6° C.melting point (Tm) with a heat of fusion of 60.0 J/g. The correspondingCRYSTAF curve shows the tallest peak at 47.6° C. with a peak area of59.5 percent. The delta between the DSC Tm and the Tcrystaf is 72.0° C.

The DSC curve for the polymer of example 6 shows a peak with a 115.2° C.melting point (Tm) with a heat of fusion of 60.4 J/g. The correspondingCRYSTAF curve shows the tallest peak at 44.2° C. with a peak area of62.7 percent. The delta between the DSC Tm and the Tcrystaf is 71.0° C.

The DSC curve for the polymer of example 7 shows a peak with a 121.3° C.melting point with a heat of fusion of 69.1 J/g. The correspondingCRYSTAF curve shows the tallest peak at 49.2° C. with a peak area of29.4 percent. The delta between the DSC Tm and the Tcrystaf is 72.1° C.

The DSC curve for the polymer of example 8 shows a peak with a 123.5° C.melting point (Tm) with a heat of fusion of 67.9 J/g. The correspondingCRYSTAF curve shows the tallest peak at 80.1° C. with a peak area of12.7 percent. The delta between the DSC Tm and the Tcrystaf is 43.4° C.

The DSC curve for the polymer of example 9 shows a peak with a 124.6° C.melting point (Tm) with a heat of fusion of 73.5 J/g. The correspondingCRYSTAF curve shows the tallest peak at 80.8° C. with a peak area of16.0 percent. The delta between the DSC Tm and the Tcrystaf is 43.8° C.

The DSC curve for the polymer of example 10 shows a peak with a 115.6°C. melting point (Tm) with a heat of fusion of 60.7 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 40.9° C. with apeak area of 52.4 percent. The delta between the DSC Tm and the Tcrystafis 74.7° C.

The DSC curve for the polymer of example 11 shows a peak with a 113.6°C. melting point (Tm) with a heat of fusion of 70.4 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 39.6° C. with apeak area of 25.2 percent. The delta between the DSC Tm and the Tcrystafis 74.1° C.

The DSC curve for the polymer of example 12 shows a peak with a 113.2°C. melting point (Tm) with a heat of fusion of 48.9 J/g. Thecorresponding CRYSTAF curve shows no peak equal to or above 30° C.(Tcrystaf for purposes of further calculation is therefore set at 30°C.). The delta between the DSC Tm and the Tcrystaf is 83.2° C.

The DSC curve for the polymer of example 13 shows a peak with a 114.4°C. melting point (Tm) with a heat of fusion of 49.4 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 33.8° C. with apeak area of 7.7 percent. The delta between the DSC Tm and the Tcrystafis 84.4° C.

The DSC for the polymer of example 14 shows a peak with a 120.8° C.melting point (Tm) with a heat of fusion of 127.9 J/g. The correspondingCRYSTAF curve shows the tallest peak at 72.9° C. with a peak area of92.2 percent. The delta between the DSC Tm and the Tcrystaf is 47.9° C.

The DSC curve for the polymer of example 15 shows a peak with a 114.3°C. melting point (Tm) with a heat of fusion of 36.2 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 32.3° C. with apeak area of 9.8 percent. The delta between the DSC Tm and the Tcrystafis 82.0° C.

The DSC curve for the polymer of example 16 shows a peak with a 116.6°C. melting point (Tm) with a heat of fusion of 44.9 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 48.0° C. with apeak area of 65.0 percent. The delta between the DSC Tm and the Tcrystafis 68.6° C.

The DSC curve for the polymer of example 17 shows a peak with a 116.0°C. melting point (Tm) with a heat of fusion of 47.0 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 43.1° C. with apeak area of 56.8 percent. The delta between the DSC Tm and the Tcrystafis 72.9° C.

The DSC curve for the polymer of example 18 shows a peak with a 120.5°C. melting point (Tm) with a heat of fusion of 141.8 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 70.0° C. with apeak area of 94.0 percent. The delta between the DSC Tm and the Tcrystafis 50.5° C.

The DSC curve for the polymer of example 19 shows a peak with a 124.8°C. melting point (Tm) with a heat of fusion of 174.8 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 79.9° C. with apeak area of 87.9 percent. The delta between the DSC Tm and the Tcrystafis 45.0° C.

The DSC curve for the polymer of comparative D shows a peak with a 37.3°C. melting point (Tm) with a heat of fusion of 31.6 J/g. Thecorresponding CRYSTAF curve shows no peak equal to and above 30° C. Bothof these values are consistent with a resin that is low in density. Thedelta between the DSC Tm and the Tcrystaf is 7.3° C.

The DSC curve for the polymer of comparative E shows a peak with a124.0° C. melting point (Tm) with a heat of fusion of 179.3 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 79.3° C. with apeak area of 94.6 percent. Both of these values are consistent with aresin that is high in density. The delta between the DSC Tm and theTcrystaf is 44.6° C.

The DSC curve for the polymer of comparative F shows a peak with a124.8° C. melting point (Tm) with a heat of fusion of 90.4 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 77.6° C. with apeak area of 19.5 percent. The separation between the two peaks isconsistent with the presence of both a high crystalline and a lowcrystalline polymer. The delta between the DSC Tm and the Tcrystaf is47.2° C.

Physical Property Testing

Polymer samples are evaluated for physical properties such as hightemperature resistance properties, as evidenced by TMA temperaturetesting, pellet blocking strength, high temperature recovery, hightemperature compression set and storage modulus ratio, G′(25°C.)/G′(100° C.). Several commercially available polymers are included inthe tests: Comparative G* is a substantially linear ethylene/1-octenecopolymer (AFFINITY®, available from The Dow Chemical Company),Comparative H* is an elastomeric, substantially linear ethylene/1-octenecopolymer (AFFINITY®EG8100, available from The Dow Chemical Company),Comparative I is a substantially linear ethylene/1-octene copolymer(AFFINITY® PL 1840, available from The Dow Chemical Company),Comparative J is a hydrogenated styrene/butadiene/styrene triblockcopolymer (KRATON™ G1652, available from KRATON Polymers), Comparative Kis a thermoplastic vulcanizate (TPV, a polyolefin blend containingdispersed therein a crosslinked elastomer). Results are presented inTable 4.

TABLE 4 High Temperature Mechanical Properties TMA-1 mm Pellet Blocking300% Strain Compression penetration Strength G′(25° C.)/ Recovery (80°C.) Set (70° C.) Ex. (° C.) lb/ft² (kPa) G′(100° C.) (percent) (percent)D* 51 — 9 Failed — E* 130 — 18 — — F* 70 141 (6.8) 9 Failed 100  5 104 0 (0) 6 81 49  6 110 — 5 — 52  7 113 — 4 84 43  8 111 — 4 Failed 41  997 — 4 — 66 10 108 — 5 81 55 11 100 — 8 — 68 12 88 — 8 — 79 13 95 — 6 8471 14 125 — 7 — — 15 96 — 5 — 58 16 113 — 4 — 42 17 108  0 (0) 4 82 4718 125 — 10 — — 19 133 — 9 — — G* 75 463 (22.2) 89 Failed 100 H* 70 213(10.2) 29 Failed 100 I* 111 — 11 — — J* 107 — 5 Failed 100 K* 152 — 3 —40

In Table 4, Comparative F (which is a physical blend of the two polymersresulting from simultaneous polymerizations using catalyst A1 and B1)has a 1 mm penetration temperature of about 70° C., while Examples 5-9have a 1 mm penetration temperature of 100° C. or greater. Further,examples 10-19 all have a 1 mm penetration temperature of greater than85° C., with most having 1 mm TMA temperature of greater than 90° C. oreven greater than 100° C. This shows that the novel polymers have betterdimensional stability at higher temperatures compared to a physicalblend. Comparative J (a commercial SEBS) has a good 1 mm TMA temperatureof about 107° C., but it has very poor (high temperature 70° C.)compression set of about 100 percent and it also failed to recover(sample broke) during a high temperature (80° C.) 300 percent strainrecovery. Thus the exemplified polymers have a unique combination ofproperties unavailable even in some commercially available, highperformance thermoplastic elastomers.

Similarly, Table 4 shows a low (good) storage modulus ratio, G′(25°C.)/G′(100° C.), for the inventive polymers of 6 or less, whereas aphysical blend (Comparative F) has a storage modulus ratio of 9 and arandom ethylene/octene copolymer (Comparative G) of similar density hasa storage modulus ratio an order of magnitude greater (89). It isdesirable that the storage modulus ratio of a polymer be as close to 1as possible. Such polymers will be relatively unaffected by temperature,and fabricated articles made from such polymers can be usefully employedover a broad temperature range. This feature of low storage modulusratio and temperature independence is particularly useful in elastomerapplications such as in pressure sensitive adhesive formulations.

The data in Table 4 also demonstrate that the polymers of the inventionpossess improved pellet blocking strength. In particular, Example 5 hasa pellet blocking strength of 0 MPa, meaning it is free flowing underthe conditions tested, compared to Comparatives F and G which showconsiderable blocking. Blocking strength is important since bulkshipment of polymers having large blocking strengths can result inproduct clumping or sticking together upon storage or shipping,resulting in poor handling properties.

High temperature (70° C.) compression set for the inventive polymers isgenerally good, meaning generally less than about 80 percent, preferablyless than about 70 percent and especially less than about 60 percent. Incontrast, Comparatives F, G, H and J all have a 70° C. compression setof 100 percent (the maximum possible value, indicating no recovery).Good high temperature compression set (low numerical values) isespecially needed for applications such as gaskets, window profiles,o-rings, and the like.

TABLE 5 Ambient Temperature Mechanical Properties Tensile 100% 300%Retractive Flex Tensile Abrasion: Notched Strain Strain Strain StressModu- Modu- Tensile Elongation Tensile Elongation Volume Tear RecoveryRecovery at 150% Compression Relaxation lus lus Strength at Break¹Strength at Break Loss Strength 21° C. 21° C. Strain Set 21° C. at 50%Ex. (MPa) (MPa) (MPa)¹ (%) (MPa) (%) (mm³) (mJ) (percent) (percent)(kPa) (Percent) Strain² D* 12 5 — — 10 1074 — — 91 83 760 — — E* 895 589— 31 1029 — — — — — — — F* 57 46 — — 12 824 93 339 78 65 400 42 —  5 3024 14 951 16 1116 48 — 87 74 790 14 33  6 33 29 — — 14 938 — — — 75 86113 —  7 44 37 15 846 14 854 39 — 82 73 810 20 —  8 41 35 13 785 14 81045 461 82 74 760 22 —  9 43 38 — — 12 823 — — — — — 25 — 10 23 23 — — 14902 — — 86 75 860 12 — 11 30 26 — — 16 1090 — 976 89 66 510 14 30 12 2017 12 961 13 931 — 1247  91 75 700 17 — 13 16 14 — — 13 814 — 691 91 — —21 — 14 212 160 — — 29 857 — — — — — — — 15 18 14 12 1127  10 1573 —2074  89 83 770 14 — 16 23 20 — — 12 968 — — 88 83 1040  13 — 17 20 18 —— 13 1252 — 1274  13 83 920  4 — 18 323 239 — — 30 808 — — — — — — — 19706 483 — — 36 871 — — — — — — — G* 15 15 — — 17 1000 — 746 86 53 110 2750 H* 16 15 — — 15 829 — 569 87 60 380 23 — I* 210 147 — — 29 697 — — —— — — — J* — — — — 32 609 — — 93 96 1900  25 — K* — — — — — — — — — — —30 — ¹Tested at 51 cm/minute ²measured at 38° C. for 12 hours

Table 5 shows results for mechanical properties for the new polymers aswell as for various comparison polymers at ambient temperatures. It maybe seen that the inventive polymers have very good abrasion resistancewhen tested according to ISO 4649, generally showing a volume loss ofless than about 90 mm³, preferably less than about 80 mm³, andespecially less than about 50 mm³. In this test, higher numbers indicatehigher volume loss and consequently lower abrasion resistance.

Tear strength as measured by tensile notched tear strength of theinventive polymers is generally 1000 mJ or higher, as shown in Table 5.Tear strength for the inventive polymers can be as high as 3000 mJ, oreven as high as 5000 mJ. Comparative polymers generally have tearstrengths no higher than 750 mJ.

Table 5 also shows that the polymers of the invention have betterretractive stress at 150 percent strain (demonstrated by higherretractive stress values) than some of the comparative samples.Comparative Examples F, G and H have retractive stress value at 150percent strain of 400 kPa or less, while the inventive polymers haveretractive stress values at 150 percent strain of 500 kPa (Ex. 11) to ashigh as about 1100 kPa (Ex. 17). Polymers having higher than 150 percentretractive stress values would be quite useful for elastic applications,such as elastic fibers and fabrics, especially nonwoven fabrics. Otherapplications include diaper, hygiene, and medical garment waistbandapplications, such as tabs and elastic bands.

Table 5 also shows that stress relaxation (at 50 percent strain) is alsoimproved (less) for the inventive polymers as compared to, for example,Comparative G. Lower stress relaxation means that the polymer retainsits force better in applications such as diapers and other garmentswhere retention of elastic properties over long time periods at bodytemperatures is desired.

Optical Testing

TABLE 6 Polymer Optical Properties Internal Haze Clarity Ex. (percent)(percent) 45° Gloss (percent) F* 84 22 49 G* 5 73 56  5 13 72 60  6 3369 53  7 28 57 59  8 20 65 62  9 61 38 49 10 15 73 67 11 13 69 67 12 875 72 13 7 74 69 14 59 15 62 15 11 74 66 16 39 70 65 17 29 73 66 18 6122 60 19 74 11 52 G* 5 73 56 H* 12 76 59 I* 20 75 59

The optical properties reported in Table 6 are based on compressionmolded films substantially lacking in orientation. Optical properties ofthe polymers may be varied over wide ranges, due to variation incrystallite size, resulting from variation in the quantity of chainshuttling agent employed in the polymerization.

Extractions of Multi-Block Copolymers

Extraction studies of the polymers of examples 5, 7 and Comparative Eare conducted. In the experiments, the polymer sample is weighed into aglass fritted extraction thimble and fitted into a Kumagawa typeextractor. The extractor with sample is purged with nitrogen, and a 500mL round bottom flask is charged with 350 mL of diethyl ether. The flaskis then fitted to the extractor. The ether is heated while beingstirred. Time is noted when the ether begins to condense into thethimble, and the extraction is allowed to proceed under nitrogen for 24hours. At this time, heating is stopped and the solution is allowed tocool. Any ether remaining in the extractor is returned to the flask. Theether in the flask is evaporated under vacuum at ambient temperature,and the resulting solids are purged dry with nitrogen. Any residue istransferred to a weighed bottle using successive washes of hexane. Thecombined hexane washes are then evaporated with another nitrogen purge,and the residue dried under vacuum overnight at 40° C. Any remainingether in the extractor is purged dry with nitrogen.

A second clean round bottom flask charged with 350 mL of hexane is thenconnected to the extractor. The hexane is heated to reflux with stirringand maintained at reflux for 24 hours after hexane is first noticedcondensing into the thimble. Heating is then stopped and the flask isallowed to cool. Any hexane remaining in the extractor is transferredback to the flask. The hexane is removed by evaporation under vacuum atambient temperature, and any residue remaining in the flask istransferred to a weighed bottle using successive hexane washes. Thehexane in the flask is evaporated by a nitrogen purge, and the residueis vacuum dried overnight at 40° C.

The polymer sample remaining in the thimble after the extractions istransferred from the thimble to a weighed bottle and vacuum driedovernight at 40° C. Results are contained in Table 7.

TABLE 7 ether ether C₈ hexane hexane C₈ residue wt. soluble soluble molesoluble soluble mole C₈ mole Sample (g) (g) (percent) percent¹ (g)(percent) percent¹ percent¹ Comp. F* 1.097 0.063 5.69 12.2 0.245 22.3513.6 6.5 Ex. 5 1.006 0.041 4.08 — 0.040 3.98 14.2 11.6 Ex. 7 1.092 0.0171.59 13.3 0.012 1.10 11.7 9.9 ¹Determined by ¹³C NMR

Additional Polymer Examples 19A-J Continuous Solution Polymerization,Catalyst A1/B2+DEZ For Examples 19A-I

Continuous solution polymerizations are carried out in a computercontrolled well-mixed reactor. Purified mixed alkanes solvent (Isopar™ Eavailable from Exxon Mobil, Inc.), ethylene, 1-octene, and hydrogen(where used) are combined and fed to a 27 gallon reactor. The feeds tothe reactor are measured by mass-flow controllers. The temperature ofthe feed stream is controlled by use of a glycol cooled heat exchangerbefore entering the reactor. The catalyst component solutions aremetered using pumps and mass flow meters. The reactor is run liquid-fullat approximately 550 psig pressure. Upon exiting the reactor, water andadditive are injected in the polymer solution. The water hydrolyzes thecatalysts, and terminates the polymerization reactions. The post reactorsolution is then heated in preparation for a two-stage devolatization.The solvent and unreacted monomers are removed during the devolatizationprocess. The polymer melt is pumped to a die for underwater pelletcutting.

For Example 19J

Continuous solution polymerizations are carried out in a computercontrolled autoclave reactor equipped with an internal stirrer. Purifiedmixed alkanes solvent (Isopar™ E available from ExxonMobil ChemicalCompany), ethylene at 2.70 lbs/hour (1.22 kg/hour), 1-octene, andhydrogen (where used) are supplied to a 3.8 L reactor equipped with ajacket for temperature control and an internal thermocouple. The solventfeed to the reactor is measured by a mass-flow controller. A variablespeed diaphragm pump controls the solvent flow rate and pressure to thereactor. At the discharge of the pump, a side stream is taken to provideflush flows for the catalyst and cocatalyst injection lines and thereactor agitator. These flows are measured by Micro-Motion mass flowmeters and controlled by control valves or by the manual adjustment ofneedle valves. The remaining solvent is combined with 1-octene,ethylene, and hydrogen (where used) and fed to the reactor. A mass flowcontroller is used to deliver hydrogen to the reactor as needed. Thetemperature of the solvent/monomer solution is controlled by use of aheat exchanger before entering the reactor. This stream enters thebottom of the reactor. The catalyst component solutions are meteredusing pumps and mass flow meters and are combined with the catalystflush solvent and introduced into the bottom of the reactor. The reactoris run liquid-full at 500 psig (3.45 MPa) with vigorous stirring.Product is removed through exit lines at the top of the reactor. Allexit lines from the reactor are steam traced and insulated.Polymerization is stopped by the addition of a small amount of waterinto the exit line along with any stabilizers or other additives andpassing the mixture through a static mixer. The product stream is thenheated by passing through a heat exchanger before devolatilization. Thepolymer product is recovered by extrusion using a devolatilizingextruder and water cooled pelletizer.

Process details and results are contained in Table 8. Selected polymerproperties are provided in Tables 9A-C.

In Table 9B, inventive examples 19F and 19G show low immediate set ofaround 65-70% strain after 500% elongation.

TABLE 8 Polymerization Conditions Cat Cat Cat A1² Cat A1 B2³ B2 DEZ DEZC₂H₄ C₈H₁₆ Solv. H₂ T Conc. Flow Conc. Flow Conc Flow Ex. lb/hr lb/hrlb/hr sccm¹ ° C. ppm lb/hr ppm lb/hr wt % lb/hr 19A 55.29 32.03 323.03101 120 600 0.25 200 0.42 3.0 0.70 19B 53.95 28.96 325.3 577 120 6000.25 200 0.55 3.0 0.24 19C 55.53 30.97 324.37 550 120 600 0.216 2000.609 3.0 0.69 19D 54.83 30.58 326.33 60 120 600 0.22 200 0.63 3.0 1.3919E 54.95 31.73 326.75 251 120 600 0.21 200 0.61 3.0 1.04 19F 50.4334.80 330.33 124 120 600 0.20 200 0.60 3.0 0.74 19G 50.25 33.08 325.61188 120 600 0.19 200 0.59 3.0 0.54 19H 50.15 34.87 318.17 58 120 6000.21 200 0.66 3.0 0.70 19I 55.02 34.02 323.59 53 120 600 0.44 200 0.743.0 1.72 19J 7.46 9.04 50.6 47 120 150 0.22 76.7 0.36 0.5 0.19 Zn⁴ Cocat1 Cocat 1 Cocat 2 Cocat 2 in Poly Conc. Flow Conc. Flow polymer Rate⁵Conv⁶ Polymer Ex. ppm lb/hr ppm lb/hr ppm lb/hr wt % wt % Eff.⁷ 19A 45000.65 525 0.33 248 83.94 88.0 17.28 297 19B 4500 0.63 525 0.11 90 80.7288.1 17.2 295 19C 4500 0.61 525 0.33 246 84.13 88.9 17.16 293 19D 45000.66 525 0.66 491 82.56 88.1 17.07 280 19E 4500 0.64 525 0.49 368 84.1188.4 17.43 288 19F 4500 0.52 525 0.35 257 85.31 87.5 17.09 319 19G 45000.51 525 0.16 194 83.72 87.5 17.34 333 19H 4500 0.52 525 0.70 259 83.2188.0 17.46 312 19I 4500 0.70 525 1.65 600 86.63 88.0 17.6 275 19J — — —— — — — — — ¹standard cm³/min²[N-(2,6-di(1-methylethyl)phenyl)amido)(2-isopropylphenyl)(α-naphthalen-2-diyl(6-pyridin-2-diyl)methane)]hafniumdimethyl³bis-(1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)immino)zirconium dimethyl ⁴ppm in final product calculated by mass balance⁵polymer production rate ⁶weight percent ethylene conversion in reactor⁷efficiency, kg polymer/g M where g M = g Hf + g Z

TABLE 9A Polymer Physical Properties Heat of CRYSTAF Density Mw MnFusion Tm TCRYSTAF Tm − TCRYSTAF Peak Area Ex. (g/cc) I2 I10 I10/I2(g/mol) (g/mol) Mw/Mn (J/g) (° C.) Tc (° C.) (° C.) (° C.) (wt %) 19A0.8781 0.9 6.4 6.9 123700 61000 2.0 56 119 97 46 73 40 19B 0.8749 0.97.3 7.8 133000 44300 3.0 52 122 100 30 92 76 19C 0.8753 5.6 38.5 6.981700 37300 2.2 46 122 100 30 92  8 19D 0.8770 4.7 31.5 6.7 80700 397002.0 52 119 97 48 72  5 19E 0.8750 4.9 33.5 6.8 81800 41700 2.0 49 121 9736 84 12 19F 0.8652 1.1 7.5 6.8 124900 60700 2.1 27 119 88 30 89 89 19G0.8649 0.9 6.4 7.1 135000 64800 2.1 26 120 92 30 90 90 19H 0.8654 1.07.0 7.1 131600 66900 2.0 26 118 88 — — — 19I 0.8774 11.2 75.2 6.7 6640033700 2.0 49 119 99 40 79 13 19J 0.8995 5.6 39.4 7.0 75500 29900 2.5 101122 106 — — —

TABLE 9B Polymer Physical Properties of Compression Molded FilmImmediate Immediate Immediate Set after Set after Set after RecoveryRecovery Recovery Density Melt Index 100% Strain 300% Strain 500% Strainafter 100% after 300% after 500% Example (g/cm³) (g/10 min) (%) (%) (%)(%) (%) (%) 19A 0.878 0.9 15 63 131  85 79 74 19B 0.877 0.88 14 49 97 8684 81 19F 0.865 1 — — 70 — 87 86 19G 0.865 0.9 — — 66 — — 87 19H 0.8650.92 — 39 — — 87 —

TABLE 9C Average Block Index For exemplary polymers¹ Example Zn/C₂ ²Average BI Polymer F 0 0 Polymer 8 0.56 0.59 Polymer 19a 1.3 0.62Polymer 5 2.4 0.52 Polymer 19b 0.56 0.54 Polymer 19h 3.15 0.59¹Additional information regarding the calculation of the block indicesfor various polymers is disclosed in U.S. patent application Ser. No.    (insert when known), entitled “Ethylene/α-Olefin BlockInterpolymers”, filed on Mar. 15, 2006, in the name of Colin L. P. Shan,Lonnie Hazlitt, et. al. and assigned to Dow Global Technologies Inc.,the disclose of which is incorporated by reference herein in itsentirety. ²Zn/C₂ * 1000 = (Zn feed flow * Zn concentration/1000000/Mw ofZn)/(Total Ethylene feed flow * (1 − fractional ethylene conversionrate)/Mw of Ethylene) * 1000. Please note that “Zn” in “Zn/C₂ * 1000”refers to the amount of zinc in diethyl zinc (“DEZ”) used in thepolymerization process, and “C2” refers to the amount of ethylene usedin the polymerization process.

Particularly Useful Ethylene/α-Olefin Multi-Block InterpolymerComponent(s) for Compositions Having Improved Hot Tack

It has been discovered that some ethylene/α-olefin multi-blockinterpolymers are particularly beneficial in compositions suitable forfilm. For example, especially useful ethylene/α-olefin multi-blockinterpolymers are those with a density (as measured in accordance withASTM D-792) generally greater than about 0.860 g/cc, preferably fromabout 0.89 g/cc to about 0.94 g/cc, more preferably from about 0.887g/cc to about 0.928 g/cc, and even more preferably from about 0.900 g/ccto about 0.925 g/cc. Interpolymers of these density can be used alone ormixed with other polymers to make compositions having improved hot tackproperties.

Similarly, the molecular weight of the aforementioned ethylene/α-olefinmulti-block interpolymers should usually be considered when selectingsaid interpolymer for a given film application. The molecular weight ofthe interpolymers is conveniently indicated using a melt indexmeasurement according to ASTM D-1238, Condition 190° C./2.16 kg(formerly known as “Condition E” and also known as 12). Melt index isinversely proportional to the molecular weight of the polymer. Thus, thehigher the molecular weight, the lower the melt index, although therelationship is not linear. The melt index for the above interpolymersthat may be especially useful for film compositions is generally fromabout 0.1 g/10 min. to about 10 g/10 min., preferably from about 0.2g/10 min. to about 5 g/10 min., and especially from about 0.5 g/10 min.to about 3 g/10 min. Interpolymers of these melt index can be used aloneor mixed with other polymers to make compositions suitable for film withbeneficial properties.

Compositions Comprising the Ethylene/α-Olefin Multi-Block InterpolymerComponent(s) Having High Hot Tack

The specific composition chosen for a given film will often depend uponthe type of film, number of layers, its desired application and desiredproperties. In addition to hot tack such properties may include, forexample, processing, strength, or adhesion characteristics. By using anappropriate composition comprising one or more of the ethylene/α-olefinmulti-block interpolymers described above enhanced performance orimproved combinations of desired properties of a film may be obtained.

In a preferred embodiment a composition comprising a singleethylene/α-olefin multi-block interpolymer described above may be used.Alternatively, a composition comprising two or more of theabove-described ethylene/α-olefin multi-block interpolymers (each havingone or more different properties) may be used. Yet another alternativeinvolves using a composition comprising one or more of theethylene/α-olefin multi-block interpolymers described above blended withone or more other polymers such as substantially linear ethyleneinterpolymers or homopolymers (SLEP), high pressure low densitypolyethylene (LDPE), ethylene/vinyl acetate copolymer (EVA),ethylene/carboxylic acid copolymers and ionomers thereof, polybutylene(PB), and α-olefin polymers such as high density polyethylene, mediumdensity polyethylene, polypropylene, ethylene/propylene interpolymers,linear low density polyethylene (LLDPE) and ultra low densitypolyethylene, as well as graft-modified polymers, and combinationsthereof including density, MWD, and/or comonomer combinations such asthose disclosed, for example, by Smith in U.S. Pat. No. 5,032,463 whichis incorporated herein by reference. For multi-layer films it may bepreferable in some circumstances that the outer film layers(alternatively referred to in the art as “skin layers” or “surfacelayers”) and/or the sealant layers comprise ethylene/α-olefinmulti-block interpolymer, substantially linear ethylene interpolymerand/or homopolymer, or a mixture thereof.

While it often depends on the desired properties, preferablecompositions for films often comprise at least about 20, more preferablyat least about 30, yet more preferably at least about 50 weight percentethylene/α-olefin multi-block interpolymer based on the total weight ofthe composition. Often it is desirable to include additional polymers orpolymer blends made with a Ziegler catalyst, a constrained geometrycatalyst, or a combination thereof. Particularly useful additionalpolymers include for example, SLEP, LLDPE, LDPE, polypropylene andblends thereof such as described in, for example, U.S. Pat. Nos.5,844,045; 5,847,053; 6,111,023 and 6,262,174. Such polymers are soldcommercially by, for example, The Dow Chemical Company and Exxon, underthe names AFFINITY®, Elite™, Dowlex™, and Exact™. The compositions ofthe present invention also are compatible and especially suited forblends with HDPE which is often used as a film barrier layer. Inaddition, blends comprising polypropylene and LDPE may achieve evenbetter hot tack properties in some situations as described in U.S. Pat.No. 6,262,174. For situations in which easy opening bags are desired, itmay be desirable to employ a heat sealable film layer comprisingethylene/α-olefin multi-block interpolymer and polybutylene or anotherbutylene polymer that is compatible with the ethylene/α-olefinmulti-block interpolymer.

The compositions above can be formed by any convenient method includingthose described in U.S. Pat. No. 6,262,174 the disclosure of which isincorporated herein in its entirety by reference. For example, theblends may be prepared by mixing or kneading the respective componentsat a temperature around or above the melt point temperature of one ormore of the components. For most ethylene/α-olefin multi-blockinterpolymer compositions, this temperature may be above 130° C., mostgenerally above 145° C., and most preferably above 150° C. Typicalpolymer mixing or kneading equipment that is capable of reaching thedesired temperatures and melt plastifying the mixture may be employed.These include mills, kneaders, extruders (both single screw andtwin-screw), Banbury mixers, calenders, and the like. The sequence ofmixing and method may depend on the final composition. A combination ofBanbury batch mixers and continuous mixers may also be employed, such asa Banbury mixer followed by a mill mixer followed by an extruder.

Another method of forming the above compositions comprises in-situpolymerization as disclosed in U.S. Pat. No. 5,844,045 in the names ofBrian W. S. Kolthammer and Robert S. Cardwell, the disclosure of whichis incorporated herein in its entirety by reference. U.S. Pat. No.5,844,045 describes inter alia, interpolymerizations of ethylene andC₃-C₂₀ alpha-olefins using at least one homogeneous catalyst in at leastone reactor and at least one heterogeneous catalyst in at least oneother reactor. The multiple reactors can be operated in series or inparallel or any combination thereof, with at least one reactor employedto make an ethylene/α-olefin multi-block interpolymer as describedabove. In this manner, blends may be made in solution processescomprising constrained geometry catalysts, Ziegler catalysts, andcombinations thereof. Such blends comprise, for example, one or moreethylene/α-olefin multi-block interpolymers (as described above and inPCT/US2005/008917 filed Mar. 17, 2004), one or more polymers of broadmolecular weight distribution (e.g. heterogeneously branched ethylenepolymers as described in, for example, U.S. Pat. No. 5,847,053), and/orone or more polymers of narrow molecular weight distribution (e.g.,homogeneous polymers as described in U.S. Pat. No. 3,645,992 (Elston) orU.S. Pat. No. 5,272,236).

In-situ polymerization using solution polymerization reactors in seriesmay be particularly preferable when making blends that comprise at leastone high molecular weight polymer of narrow molecular weightdistribution and at least one polymer of broad molecular weightdistribution made with a Ziegler catalyst. This is because it oftenrequires substantial solvent to make high molecular weight polymer whilethe use of Ziegler catalysts often requires higher temperatures thanhomogeneous catalysts. Thus, the use of higher temperatures with theZiegler catalyst in a subsequent reactor will facilitate excess solventevaporation. In addition, another advantage to using series solutionreactors to make the products of the invention is that an extremely highmolecular weight product (e.g., I₂ of 0.05 g/10 minutes or less) can bemade and incorporated into the finished product, even though thatextremely high molecular weight product often could not physically beisolated without catastrophic reactor fouling. So for those “blends”incorporating a very high molecular weight component, a discrete orphysical blend is often not even possible, since the first componentcould not be isolated.

Other general guidelines can be used by those in skill in the art toselect a composition for a film with desired properties. For example, ithas been found that ethylene/α-olefin multi-block interpolymers madewith larger amounts of chain shuttling agents tend to exhibit lowerinitiation temperatures and broader hot tack windows.

Depending on the amount and type of chain shuttling agent employed tomake the ethylene/α-olefin multi-block interpolymer, the compositions ofthe present invention may further comprise the residue of the chainshuttling agent or agents that were employed. By residue is meant ananalytically detectable amount of either the original chain shuttlingagent or a derivative thereof, e.g., zinc or aluminum compounds.

Useful Additives

Additives such as antioxidants (e.g., hindered phenolics (such asIrganox® 1010 or Irganox® 1076), phosphites (e.g., Irgafos® 168 alltrademarks of Ciba Geigy), processing aids, cling additives (e.g., PIB),PEPQ™ (a trademark of Sandoz Chemical, the primary ingredient of whichis believed to be a biphenylphosphonite), slip, pigments, colorants,fillers, and the like can also be included in the compositions, to theextent that they do not interfere with the desired properties. Thefabricated film may also contain additives to enhance its antiblockingand coefficient of friction characteristics including, but not limitedto, untreated and treated silicon dioxide, talc, calcium carbonate, andclay, as well as primary and secondary fatty acid amides, siliconecoatings, etc. Other additives to enhance the film's anti-foggingcharacteristics may also be added, as described, for example, in U.S.Pat. No. 4,486,552 (Niemann), the disclosure of which is incorporatedherein by reference. Still other additives, such as quaternary ammoniumcompounds alone or in combination with EAA or other functional polymers,may also be added to enhance the film's antistatic characteristics andallow packaging of electronically sensitive goods.

Heat Sealable Films Made with Compositions of the Present Invention

Films prepared from the compositions of the present inventionadvantageously have desirable properties such as good seal strength, lowinitiation temperatures, high ultimate hot tack, and wide processingwindows. For example, 2 mil monolayer blown films made with compositionsof the present invention often have high hot tack, e.g., ultimate hottack above about 1, preferably above about 2, more preferably aboveabout 3, even more preferably above about 4 N/in based upon ASTM F 1921,Standard Test Methods for Hot Seal Strength (Hot Tack) of ThermoplasticPolymers and Blends Comprising the Sealing Surfaces of Flexible Webs,Method B with a dwell time of 0.5 seconds and cooling time of 0.1seconds. The ultimate (or peak) hot tack strength is typically obtainedat sealing temperatures at least about 15, preferably at least about 20°C. below the peak melting temperature of the polymer as measured by DSC.Two mil monolayer films made with compositions of the present inventionalso often have a hot tack of greater than 1 N/in over a temperaturerange of at least about 20, more preferably at least about 30, morepreferably at least about 40, even more preferably at least about 45° C.based upon ASTM F 1921, Method B with a dwell time of 0.5 seconds andcooling time of 0.1 seconds. The seal strength is typically above about3.75, preferably above about 3.9, more preferably above about 4, evenmore preferably above about 4.1 lb/in using ASTM F88, Standard TestMethod for Seal Strength of Flexible Barrier Materials.

The hot tack temperature window is defined here as the temperaturewindow for which the hot tack strength of the joint is above a specifiedvalue, such as 0.5 N/linear inch.

The broad hot tack temperature window of the compositions of the presentinvention often begins substantially below, e.g., at least about 25° C.,preferably at least about 35° C., the peak melting temperature via DSCof the composition. In comparison, the comparative example showed hottack initiation temperature of above 0.5 N/linear inch at about 10-15°C. below the peak melting temperature via DSC. This allows one toreadily control the desired seal strength by modifying the sealingtemperature to balance the seal strength and hot tack strength. Theseproperties also allow for higher temperature resistance in applicationsthat require it, e.g., steam sterilization of packaged food.

Heat sealable films made with the composition of the present inventionmay be employed in either monolayer or multilayer film structures or aslaminates. Multilayer film structures are preferred. Regardless of howthe film is utilized, it may be prepared by a variety of processes thatare well known to those of skill in the art.

Film structures may be made by conventional fabrication techniques, e.g.simple bubble extrusion, biaxial orientation processes (such as tenterframes or double bubble processes), simple cast/sheet extrusion,coextrusion, lamination, etc. Conventional simple bubble extrusionprocesses (also known as hot blown film processes) are described, forexample, in The Encyclopedia of Chemical Technology, Kirk-Othmer, ThirdEdition, John Wiley & Sons, New York, 1981, Vol. 16, pp. 416-417 andVol. 18, pp. 191-192, the disclosures of which are incorporated hereinby reference.

“Stretched” and “oriented” are used in the art and hereininterchangeably, although orientation is actually the consequence of afilm being stretched by, for example, internal air pressure pushing onthe tube or by a tenter frame pulling on the edges of the film.

Biaxial orientation film manufacturing processes such as described inthe “double bubble” process of U.S. Pat. No. 3,456,044 (Pahlke), and theprocesses described in U.S. Pat. No. 4,352,849 (Mueller), U.S. Pat. Nos.4,820,557 and 4,837,084 (both to Warren), U.S. Pat. No. 4,865,902(Golike et al.), U.S. Pat. No. 4,927,708 (Herran et al.), U.S. Pat. No.4,952,451 (Mueller), and U.S. Pat. Nos. 4,963,419 and 5,059,481 (both toLustig et al.), the disclosures of which are incorporated herein byreference, can also be used to make the novel film structures of thisinvention. Biaxially oriented film structures can also be made by atenter-frame technique, such as that used for oriented polypropylene.

As disclosed by Pahlke in U.S. Pat. No. 3,456,044 and in comparison tothe simple bubble method, “double bubble” or “trapped bubble” filmprocessing can significantly increase a film's orientation in both themachine and transverse directions. The increased orientation yieldshigher free shrinkage values when the film is subsequently heated. Also,Pahlke in U.S. Pat. No. 3,456,044 and Lustig et al. in U.S. Pat. No.5,059,481 (incorporated herein by reference) disclose that low densitypolyethylene and ultra low density polyethylene materials, respectively,exhibit poor machine and transverse shrink properties when fabricated bythe simple bubble method, e.g., about 3% free shrinkage in bothdirections. However, in contrast to known film materials, andparticularly in contrast to those disclosed by Lustig et al. in U.S.Pat. Nos. 5,059,481; 4,976,898; and 4,863,769, as well as in contrast tothose disclosed by Smith in U.S. Pat. No. 5,032,463 (the disclosures ofwhich are incorporated herein by reference), the unique interpolymercompositions of the present invention may show significantly improvedsimple bubble shrink characteristics in both the machine and transversedirections. Additionally, when the unique interpolymers may befabricated by simple bubble method at high blow-up ratios, e.g., atgreater or equal to 2.5:1, or, more preferably, by the “double bubble”method disclosed by Pahlke in U.S. Pat. No. 3,456,044 and by Lustig etal. in U.S. Pat. No. 4,976,898, it is possible to achieve good machineand transverse direction shrink characteristics making the resultantfilms suitable for shrink wrap packaging purposes. Blow-Up Ratio,abbreviated herein as “BUR”, is calculated by the equation:

BUR=Bubble Diameter v. Die Diameter.

The olefin packaging and wrapping films made from compositions of thepresent invention may be monolayer or multilayer films. The film madefrom the novel compositions can also be coextruded with the otherlayer(s) or the film can be laminated onto another layer(s) in asecondary operation, such as that described in Packaging Foods WithPlastics, by Wilmer A. Jenkins and James P. Harrington (1991) or thatdescribed in “Coextrusion For Barrier Packaging” by W. J. Schrenk and C.R. Finch, Society of Plastics Engineers RETEC Proceedings, Jun. 15-17(1981), pp. 211-229 or in “Coextrusion Basics” by Thomas 1. Butler, FilmExtrusion Manual: Process, Materials, Properties. pp. 31-80 (publishedby TAPPI Press (1992)), the disclosures of which is incorporated hereinby reference. If a monolayer film is produced via tubular film (i.e.,blown film techniques) or flat die (i.e., cast film) as described by K.R. Osborn and W. A. Jenkins in “Plastic Films, Technology and PackagingApplications” (Technomic Publishing Co., Inc. (1992)), the disclosure ofwhich is incorporated herein by reference, then the film must go throughan additional post-extrusion step of adhesive or extrusion lamination toother packaging material layers to form a multilayer structure. If thefilm is a coextrusion of two or more layers (also described by Osbornand Jenkins), the film may still be laminated to additional layers ofpackaging materials, depending on the other physical requirements of thefinal film. “Laminations Vs. Coextrusion” by D. Dumbleton (ConvertingMagazine (September 1992), the disclosure of which is incorporatedherein by reference, also discusses lamination versus coextrusion.Monolayer and coextruded films can also go through other post extrusiontechniques, such as a biaxial orientation process.

In certain embodiments of this invention, at least one heat sealable,innermost or outermost layer (i.e., skin layer) of a film structurecomprises one or more ethylene/α-olefin multi-block interpolymers. Thisheat sealable layer can be coextruded with other layer(s) or the heatsealable layer can be laminated onto another layer(s) or substrate in asecondary operation, such as that described in Packaging Foods WithPlastics, ibid, or that described in “Coextrusion For Barrier Packaging”by W. J. Schrenk and C. R. Finch, Society of Plastics Engineers RETECProceedings June 15-17 (1981), pp. 211-229, the disclosures of which areincorporated herein by reference. Preferable substrates include papers,foils, oriented polypropylenes such as industrial grade or BICOR LBW®,polyamides, polyesters, polyethylenes, polyethylene terephthalate, and,metallized substrates.

Should a multilayer film be desired, such may be obtained from amonolayer film which has been previously produced via tubular film(i.e., blown film techniques) or flat die (i.e. cast film) as describedby K. R. Osborn and W. A. Jenkins in “Plastic Films, Technology andPackaging Applications” (Technomic Publishing Co., Inc. (1992)), thedisclosures of which are incorporated herein by reference, wherein thesealant film must go through an additional post-extrusion step ofadhesive or extrusion lamination to other packaging material layers. Ifthe sealant film is a coextrusion of two or more layers (also describedby Osborn and Jenkins), the film may still be laminated to additionallayers of packaging materials, depending on the other physicalrequirements of the final packaging film. “Laminations vs. Coextrusions”by D. Dumbleton (Converting Magazine, September 1992), the disclosure ofwhich is incorporated herein by reference, also discusses laminationversus coextrusion. Monolayer and coextruded films can also go throughother post-extrusion techniques, such as a biaxial orientation processand irradiation. With respect to irradiation, this technique can alsoprecede extrusion by irradiating the pellets from which the film is tobe fabricated prior to feeding the pellets into the extruder, whichincreases the melt tension of the extruded polymer film and enhancesprocessability.

Extrusion coating is yet another technique for producing packagingmaterials. Similar to cast film, extrusion coating is a flat dietechnique. A heat-sealable film comprised of the compositions of thepresent invention can be extrusion coated onto a substrate either in theform of a monolayer or a coextruded extrudate according to, for example,the processes described in U.S. Pat. No. 4,339,507 incorporated hereinby reference. Utilizing multiple extruders or by passing the varioussubstrates through the extrusion coating system several times can resultin multiple polymer layers each providing some sort of performanceattribute whether it be barrier, toughness, or improved hot tack or heatsealability. Some typical end use applications formulti-layered/multi-substrate systems are for cheese packages. Other enduse applications include, but are not limited to moist pet foods,snacks, chips, frozen foods, meats, hot dogs, and numerous otherapplications.

Generally for a multilayer film structure, the novel compositionsdescribed herein comprise at least one layer of the total multilayerfilm structure. Other layers of the multilayer structure may be includedto provide a variety of performance attributes. Other layers of themultilayer structure include but are not limited to barrier layers,and/or tie layers, and/or structural layers. Various materials can beused for these layers, with some of them being used as more than onelayer in the same film structure. Some of these materials include: foil,nylon, ethylene/vinyl alcohol (EVOH) copolymers, poly(ethyleneterephthalate) (PET), polyvinylidene chloride (PVDC), polyethyleneterephthalate (PET), oriented polypropylene (OPP), ethylene/vinylacetate (EVA) copolymers, ethylene/acrylic add (EAA) copolymers,ethylene/methacrylic add (EMAA) copolymers, LLDPE, HDPE, LDPE, nylon,graft adhesive polymers (e.g., maleic anhydride grafted polyethylene),styrene-butadiene polymers (such as K-resins, available from PhillipsPetroleum), and paper. Generally, the multilayer film structurescomprise from 2 to about 7 layers.

The thickness of the multilayer structures is typically from about 0.5mil to about 4 mils (total thickness). The heat sealable film layervaries in thickness depending on whether it is produced via coextrusionor lamination of a monolayer or coextruded film to other packagingmaterials. In a coextrusion, the heat sealable film layer is typicallyfrom about 0.1 to about 3 mils, preferably from about 0.4 to about 2mils. In a laminated structure, the monolayer or coextruded heatsealable film layer is typically from about 0.5 to about 2 mils,preferably from about 1 to 2 mils. For a monolayer film, the thicknessis typically between about 0.4 mil to about 4 mils, preferably betweenabout 0.8 to about 2.5 mils.

The heat sealable films of the invention can be made into packagingstructures such as form-fill-seal structures or bag-in-box structures.For example, one such form-fill-seal operation is described in PackagingFoods With Plastics, ibid, pp. 78-83. Packages can also be formed frommultilayer packaging roll stock by vertical or horizontal form-fill-sealpackaging and thermoform-fill-seal packaging, as described in “PackagingMachinery Operations: No. 8, Form-Fill-Sealing, A Self-InstructionalCourse” by C. G. Davis, Packaging Machinery Manufacturers Institute(April 1982); The Wiley Encyclopedia of Packaging Technology by M.Bakker (Editor), John Wiley & Sons (1986), pp. 334, 364-369; andPackaging: An Introduction by S. Sacharow and A. L. Brody, HarcourtBrace Javanovich Publications, Inc. (1987), pp. 322-326. The disclosuresof all of the preceding publications are incorporated herein byreference. A particularly useful device for form-fill-seal operations isthe Hayssen Ultima Super CMB Vertical Form-Fill-Seal Machine. Othermanufacturers of pouch thermoforming and evacuating equipment includeCryovac and Koch. A process for making a pouch with a verticalform-fill-seal machine is described generally in U.S. Pat. Nos.4,503,102 and 4,521,437, both of which are incorporated herein byreference. Film structures containing one or more layers comprising aheat sealable film of the present invention are well suited for thepackaging of potable water, wine, cheese, potatoes, condiments, andsimilar food products in such form-fill-seal structures.

The film structures made with both the interpolymers described hereinmay also be pre-formed by any known method, such as, for example, byextrusion thermoforming, with respect to the shape and contours of theproduct to be packaged. The benefit of employing pre-formed filmstructures will be to complement or avoid a given particular of apackaging operation such as augment drawability, reduced film thicknessfor given draw requirement, reduced heat up and cycle time, etc.

Film structures made from the ethylene/α-olefin multi-blockinterpolymers described herein may show surprisingly more efficientirradiation crosslinking as compared to a comparative conventionalZiegler polymerized linear ethylene/α-olefin polymer. As one aspect ofthis invention, by taking advantage of the irradiation efficient ofthese unique polymers, it possible the prepare film structures withdifferentially or selectively crosslinked film layers. To take furtheradvantage of this discovery, specific film layer materials including thepresent ethylene/α-olefin multi-block interpolymers can be formulatedwith pro-rad agents, such as triallyl cyanurate as described by Warrenin U.S. Pat. No. 4,957,790, and/or with antioxidant crosslinkinhibitors, such as butylated hydroxytoluene as described by Evert etal. in U.S. Pat. No. 5,055,328.

Irradiation crosslinking is also useful for increasing the shrinktemperature range and the heat seal range for the film structures. Forexample, U.S. Pat. No. 5,089,321, incorporated herein by reference,discloses multilayer film structures comprising at least one heatsealable outer layer and at least one core layer which have goodirradiation crosslinking performance. Among irradiation crosslinkingtechnologies, beta irradiation by electron beam sources and gammairradiation by a radioactive element such as Cobalt 60 are the mostcommon methods of crosslinking film materials.

In an irradiation crosslinking process, a thermoplastic film isfabricated by a blown film process and then exposed to an irradiationsource (beta or gamma) at an irradiation dose of up to 20 Mrad tocrosslink the polymeric film. Irradiation crosslinking can be inducedbefore or after final film orientation whenever oriented films aredesired such as for shrink and skin packaging, however, preferablyirradiation crosslinking is induced before final orientation. Whenheat-shrinkable and skin packaging films are prepared by a process wherepellet or film irradiation precedes final film orientation, the filmsinvariably show higher shrink tension and will tend yield higher packagewarpage and board curl; conversely, when orientation precedesirradiation, the resultant films will show lower shrink tension. Unlikeshrink tension, the free shrink properties of the ethylene/α-olefinmulti-block interpolymers of the present invention are believed to beessentially unaffected by whether irradiation precedes or follows finalfilm orientation.

Irradiation techniques useful for treating the film structures describedherein include techniques known to those skilled in the art. Preferably,the irradiation is accomplished by using an electron beam (beta)irradiation device at a dosage level of from about 0.5 megarad (Mrad) toabout 20 Mrad. Shrink film structures fabricated from theethylene/α-olefin multi-block interpolymers as described herein are alsoexpected to exhibit improved physical properties due to a lower degreeof chain scission occurring as a consequence of the irradiationtreatment.

The interpolymers, blends, and films of this invention, and the methodsfor preparing them, are more fully described in the following examples.

Examples 1-2 of the Present Invention—Monolayer Blown Films

Ethlylene-octene and ethylene-butene multi-block interpolymers used inExamples 1 and 2 below were prepared as described in PCT Application No.PCT/US2005/008917, filed on Mar. 17, 2005, which in turn claims priorityto U.S. Provisional Application No. 60/553,906, filed Mar. 17, 2004 eachof which is incorporated by reference herein. The comparative example isa random ethylene-octene copolymer prepared using a constrained geometrycatalyst such as those sold under the name AFFINITY® by The Dow ChemicalCompany. The polymers have a melt index of about 1 g/10 min.

Monolayer blown films of the olefin block copolymers and that of thecomparative example were prepared using a Davis-Standard blown filmcoextrusion line equipped with three Davis-Standard Model DS075HM ¾″inch extruders with 24:1 L/D ratios which feed a 2 inch diameter blowndie with a nominal 0.033″ die gap. The output rate was about 2.8 poundsper hour or 0.05 lb/hr/rpm. The extruder zone temperatures are set at330/350/390 and 400 F for Zone 1/2/3 and die zone. The film thicknesswas 2 mil at a blow-up-ratio (BUR) of 2.1:1 and a nip line speed ofabout 7 foot per minute (fpm).

The hot tack strength and seal strength of the blown films weremeasured. The hot tack, or hot seal strength was measured based uponASTM F 1921, Method B. The term “Hot tack” is used as an expression forthe strength of the heat seals immediately after the sealing operationand before the seal cools to ambient temperature. The dwell time was 0.5seconds at pre-set temperatures; the cooling time was 0.1 seconds.

The term “seal strength” is the strength of the heat seals after theyhave been allowed to cool to ambient temperature. The heat seal strengthwas measured based upon ASTM Standard Test Method E88, STM for SealStrength of Flexible Barrier Materials. The test result is a measure ofthe force required to pull apart the heat seal, or the force required tobreak the film in cases where the film breaks before the heat sealparts.

The results give the heat seal strength in terms of the sealingtemperature. The data are tabulated in Table A:

TABLE A Hot tack and heat seal strength of blown films ComparativeProperty Unit Example 1 Example 2 Example Comonomers Ethylene/ Ethylene/Ethylene/ octene butene octene Density of resin g/cc 0.901 0.901 0.902Film thickness mil 2 2 2 Peak hot tack N/in 4.7 2.4 0.7 Peak temperature° C. 110 105 85 Temperature window for hot tack >50 >40 10-15 >0.5 N/in,° C. Temperature window for hot tack 40 30 — >1 N/in, ° C. Peak heatseal strength lb/in 4.41 4.16 5.16

The hot tack strength vs. hot tack sealing temperature is shown in TableB.

TABLE B Hot tack strength (N/in) as a function of hot tack sealingtemperatures of blown films Comparative Example 1 Example 2 Example HotTack Ethylene/ Ethylene/ Ethylene/ Temperature Comonomers octene buteneoctene  50° C. 0.13 — —  60° C. 1.14 — —  70° C. 1.63 0.32 0.35  80 1.940.89 0.72  90° C. 2.28 0.96 0.38 100° C. 2.75 1.92 0.12 110° C. 0.132.92 — 120° C. — 0.23 —

Example 3 of the Present Invention—Multi-Layer Co-Extruded Film

Ethlylene-octene multi-block interpolymers used in Example 3 below wasprepared as described in PCT Application No. PCT/US2005/008917, filed onMar. 17, 2005, which in turn claims priority to U.S. ProvisionalApplication No. 60/553,906, filed Mar. 17, 2004 each of which isincorporated by reference herein. The comparative example is a randomethylene-octene copolymer prepared using a constrained geometry catalystsuch as those sold under the name AFFINITY® by The Dow Chemical Company.The polymers have a melt index of about 1 g/10 min.

Three layer co-extruded film of the olefin block copolymer (OBC) andthat of the comparative example were prepared using conventionalco-extrusion techniques. The co-extruded films have three layers: abacking layer, a tie layer and the sealant layer. The inventive exampleis compared with a reference film having the same backing layer and tielayer, but differing in the sealant layer composition. Specifically, thebacking layer is 1 mil in thickness, made of 100% Capron CA95QP(Supplied by BASF Corporation). The tie layer is 1 mil in thickness,made of 85% DOWLEX 2045G (LLDPE) (Supplied by The Dow Chemical Company)and 15% AMPLIFY GR205 (Maleic anhydride modified polyethylene,HDPE-g-MAH) (Supplied by The Dow Chemical Company). The sealant layercontains 5% Ampacet 100329 and 2.5% Ampacet 100432 with the remainderOBC or AFFINITY®. The film comprises layers of 1.5 mil sealant/1.0 miltie/1.0 mil backing.

The hot tack strength and heat seal strength were measured in a similarmanner as described above for Examples 1 and 2. The results are shownbelow.

Comparison of hot tack behaviors of 3-layer coextruded films.

Inventive Example Reference (prior art) Sealant main componentTemperature OBC, 1MI, 0.897 g/cm3 AFFINITY ® PL1880G (1MI, Temperature(62/38, .869/.945) 0.900 g/cm3) (° C.) Hot tack strength (N/in) Hot tackstrength (N/in) 70 0.07 NA 80 1.64 0.06 90 7.68 2.37 110 7.37 6.68 1205.61 5.19Comparison of heat seal data of 3-layer coextruded films having layerthickness of 1.5/1.0/1.0 mil of sealant/tie/backing layers.

Inventive Example Reference (prior art) Sealant main componentTemperature OBC, 1MI, 0.897 g/cm3 AFFINITY ® PL1880G (1MI, Temperature(62/38, .869/.945) 0.900 g/cm3) (° C.) Hot seal strength (lb/in) Hotseal strength (lb/in) 80 0.36 NA 90 7.5 0.67 100 8.7 7.5 110 10.8 7.9120 10.9 7.9 130 10.9 7.9 140 12.3 8.5 150 11.2 8.4

The inventive example showed lower hot tack initiation temperature withsimilar or higher hot tack strength compared to the Reference.Similarly, the inventive example showed lower heat seal initiationtemperature and higher heat seal strength compared to the Reference.

While the invention has been described with respect to a limited numberof embodiments, the specific features of one embodiment should not beattributed to other embodiments of the invention. No single embodimentis representative of all aspects of the invention. In some embodiments,the compositions or methods may include numerous compounds or steps notmentioned herein. In other embodiments, the compositions or methods donot include, or are substantially free of, any compounds or steps notenumerated herein. Variations and modifications from the describedembodiments exist. Finally, any number disclosed herein should beconstrued to mean approximate, regardless of whether the word “about” or“approximately” is used in describing the number. The appended claimsintend to cover all those modifications and variations as falling withinthe scope of the invention.

1. A heat-sealable film layer composition comprising at least oneethylene/a olefin interpolymer, wherein the ethylene/α-olefininterpolymer comprises at least 60 mole percent ethylene, a molecularweight distribution, Mw/Mn, greater than about 1.3, and is characterizedby one or more of the following: (a) a molecular fraction which elutesbetween 40° C. and 130° C. when fractionated using TREF, characterizedin that the fraction has a block index of at least 0.5 and up to about1; or (b) an average block index greater than zero and up to about 1.0.2. The heat-sealable film layer composition of claim 1 wherein thedensity is from about 0.860 g/cc to about 0.925 g/cc.
 3. Theheat-sealable film layer composition of claim 1 wherein the melt index(12) is from about 0.5 g/10 min. to about 3 g/10 min.
 4. Theheat-sealable film layer composition of claim 1 wherein the ultimate hottack is above about 2 N/in based upon ASTM F 1921, Method B.
 5. Theheat-sealable film layer composition of claim 1 wherein a 2 milmonolayer film of said composition has a hot tack of greater than about1 N/in over a temperature range of at least about 20° C.
 6. Theheat-sealable film layer composition of claim 1 wherein a 2 milmonolayer film of said composition has a hot tack of greater than 1 N/inover a temperature range of at least about 40° C.
 7. The heat-sealablefilm layer composition of claim 1 wherein the ethylene/α-olefininterpolymer is an ethylene-octene copolymer.
 8. The heat-sealable filmlayer composition of claim 1 wherein the ethylene/α-olefin interpolymeris an ethylene-butene copolymer.
 9. The heat-sealable film layercomposition of claim 1 wherein the ethylene/α-olefin interpolymer is anethylene-hexene copolymer.
 10. The heat-sealable film layer compositionof claim 1 wherein the composition is suitable for a blown film layer.11. The heat-sealable film layer composition of claim 1 furthercomprising at least one other different polymer selected from the groupconsisting of polyethylene, polypropylene, polyvinyl chloride,ethylene-propylene copolymer, ethylene-co-vinyl acetate, terpolymer ofethylene, propylene, a nonconjugated diene, a mixed polymer of ethyleneand vinyl acetate, a styrene-butadiene mixed polymers and combinationsthereof.
 12. The heat-sealable film layer composition of claim 1 whereinthe ethylene/α-olefin interpolymer has an average block index of fromabout 0.1 to about 0.3.
 13. The heat-sealable film layer composition ofclaim 1 wherein the ethylene/α-olefin interpolymer has an average blockindex of from about 0.3 to about 0.8.
 14. A multi-layer film structurecomprising the heat-sealable film layer composition of claim 1 as asealant layer.
 15. The multi-layer film structure of claim 14 whichfurther comprises, a backing layer, and a tie layer.
 16. A multi-layerfilm structure comprising a sealant layer which comprises at least oneethylene/a olefin interpolymer, wherein the ethylene/α-olefininterpolymer comprises at least 60 mole percent ethylene, a molecularweight distribution, Mw/Mn, greater than about 1.3, and is characterizedby one or more of the following: (a) has a Mw/Mn from about 1.7 to about3.5, at least one melting point, Tm, in degrees Celsius, and a density,d, in grams/cubic centimeter, wherein the numerical values of Tm and dcorrespond to the relationship:Tm>−2002.9+4538.5(d)−2422.2(d)²; or (b) has a Mw/Mn from about 1.7 toabout 3.5, and is characterized by a heat of fusion, ΔH in J/g, and adelta quantity, AT, in degrees Celsius defined as the temperaturedifference between the tallest DSC peak and the tallest CRYSTAF peak,wherein the numerical values of ΔT and ΔH have the followingrelationships:ΔT>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g,ΔT≧48° C. for ΔH greater than 130 J/g, wherein the CRYSTAF peak isdetermined using at least 5 percent of the cumulative polymer, and ifless than 5 percent of the polymer has an identifiable CRYSTAF peak,then the CRYSTAF temperature is 30° C.; or (c) is characterized by anelastic recovery, Re, in percent at 300 percent strain and 1 cyclemeasured with a compression-molded film of the ethylene/α-olefininterpolymer, and has a density, d, in grams/cubic centimeter, whereinthe numerical values of Re and d satisfy the following relationship whenethylene/α-olefin interpolymer is substantially free of a cross-linkedphase:Re>1481−1629(d); or (d) has a molecular fraction which elutes between40° C. and 130° C. when fractionated using TREF, characterized in thatthe fraction has a molar comonomer content of at least 5 percent higherthan that of a comparable random ethylene interpolymer fraction elutingbetween the same temperatures, wherein said comparable random ethyleneinterpolymer has the same comonomer(s) and has a melt index, density,and molar comonomer content (based on the whole polymer) within 10percent of that of the ethylene/α-olefin interpolymer; or (e) has astorage modulus at 25° C., G′(25° C.), and a storage modulus at 100° C.,G′(100° C.), wherein the ratio of G′(25° C.) to G′(100° C.) is in therange of about 1:1 to about 9:1; or (f) a molecular fraction whichelutes between 40° C. and 130° C. when fractionated using TREF,characterized in that the fraction has a block index of at least 0.5 andup to about 1; or (g) an average block index greater than zero and up toabout 1.0.
 17. The multi-layer film structure of claim 16 wherein thesealant layer has a thickness of less than about 2 mils.
 18. Themulti-layer film structure of claim 16 wherein the ultimate hot tack isabove about 2 N/in based upon ASTM F 1921, Method B.
 19. The multi-layerfilm structure of claim 16 wherein the ethylene/α-olefin interpolymerhas a density of from about 0.860 g/cc to about 0.925 g/cc.
 20. Themulti-layer film structure of claim 16 wherein the ethylene/α-olefininterpolymer comprises at least about 20 weight percent of said sealantlayer.